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How would YOU do this?

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  • CLevinski
    Hi, While I ve done a number of small projects on my lathe, my mini-mill is definitely underutilized. So I started a little project today that involves taking
    Message 1 of 24 , May 11, 2013
      Hi,

      While I've done a number of small projects on my lathe, my mini-mill is definitely underutilized.  So I started a little project today that involves taking a 1.150 x 1.850 inch piece of aluminum I had lying around, and sizing it to make a widget.  Only problem is that it was almost 1.500 inches thick, and I need it to be 1.000 inches thick.  So I thought, "Nah, I don't need to use the band saw!  I'll just mill that puppy down.".  Almost 2 hours of continuous milling later (while wearing hearing protection, because I haven't made a belt drive conversion), it is now down to 1.250 inches.  I'm face milling with a 5/8 inch end mill, only engaging about 1/3 of the diameter, never climb milling, and cutting in all four directions.  (Essentially cutting in a counter-clockwise rectangle.)  I'm running the mini-mill fairly slowly (maybe 600 RPM?, though I tried it nearer to 900 RPM and didn't pick up any noticeable benefit except for greater swarf-throwing range).  I tried cuts from .020 to .030 inches and settled on .025 inches as maximum material removal without excess noise.

      I have a fly cutter set (though I've never used it) but fly cutters are primarily for finishing cuts, I understand, so I don't think that's the solution.

      So my question; how would YOU more experienced guys do this?  Is there a technique I'm missing that would allow me to do this faster?  Since this isn't a finishing cut, could I use the full end mill width?  That would certainly speed up the process but I read that it's bad for the end mill (specially a four-flute) since one side is conventional milling and the other side is climb milling.

      And yes, if I can't find a better way, I'll probably go back to the band saw and then make a couple of passes with the mill to finish the surface.

      Times like this, I wish I had a Bridgeport.  But I don't think I'd be able to carry it down the cellar steps... ;)

      Thanks,
      Charlie

    • Benjamin Bucceri
      Well, you raise a good point with your widget project. What I would do, and what I have done, is invest in a much larger mill/drill. Not as accurate but this
      Message 2 of 24 , May 11, 2013

        Well, you raise a good point with your widget project.  What I would do, and what I have done, is invest in a much larger mill/drill.  Not as accurate but this 2 HP unit is really good at taking off the material.  The mill/drill is a Grizzly too. I use it for bigger projects, or where I have to mill stuff like stainless.  I then would finish on the mini.

         

        BTW, why so slow on the mill if you were cutting aluminum?

         


        From: GrizHFMinimill@yahoogroups.com [mailto: GrizHFMinimill@yahoogroups.com ] On Behalf Of CLevinski
        Sent: Saturday, May 11, 2013 1:49 PM
        To: GrizHFMinimill@yahoogroups.com
        Subject: [GrizHFMinimill] How would YOU do this?

         

         

         

         

         

         

        Hi,

        While I've done a number of small projects on my lathe, my mini-mill is definitely underutilized.  So I started a little project today that involves taking a 1.150 x 1.850 inch piece of aluminum I had lying around, and sizing it to make a widget.  Only problem is that it was almost 1.500 inches thick, and I need it to be 1.000 inches thick.  So I thought, "Nah, I don't need to use the band saw!  I'll just mill that puppy down.".  Almost 2 hours of continuous milling later (while wearing hearing protection, because I haven't made a belt drive conversion), it is now down to 1.250 inches.  I'm face milling with a 5/8 inch end mill, only engaging about 1/3 of the diameter, never climb milling, and cutting in all four directions.  (Essentially cutting in a counter-clockwise rectangle.)  I'm running the mini-mill fairly slowly (maybe 600 RPM?, though I tried it nearer to 900 RPM and didn't pick up any noticeable benefit except for greater swarf-throwing range).  I tried cuts from .020 to .030 inches and settled on .025 inches as maximum material removal without excess noise.

        I have a fly cutter set (though I've never used it) but fly cutters are primarily for finishing cuts, I understand, so I don't think that's the solution.

        So my question; how would YOU more experienced guys do this?  Is there a technique I'm missing that would allow me to do this faster?  Since this isn't a finishing cut, could I use the full end mill width?  That would certainly speed up the process but I read that it's bad for the end mill (specially a four-flute) since one side is conventional milling and the other side is climb milling.

        And yes, if I can't find a better way, I'll probably go back to the band saw and then make a couple of passes with the mill to finish the surface.

        Times like this, I wish I had a Bridgeport .  But I don't think I'd be able to carry it down the cellar steps... ;)

        Thanks,
        Charlie

      • CLevinski
        Hi, Ben, Well, as much as I like your solution (bigger is always better and all that), it does seem to be kind of pricey to make a little part I could probably
        Message 3 of 24 , May 11, 2013
          Hi, Ben,

          Well, as much as I like your solution (bigger is always better and all
          that), it does seem to be kind of pricey to make a little part I could
          probably buy for $25 if I didn't want a project to build.

          Good point regarding the speed... I guess it calculates to around 1900
          RPM, at least by my rule of thumb. Maybe I'll try a speed in that range
          when I resume and see if it cuts my time significantly.

          Thanks,
          Charlie

          --- In GrizHFMinimill@yahoogroups.com, "Benjamin Bucceri" wrote:
          >
          > Well, you raise a good point with your widget project. What I would
          do, and
          > what I have done, is invest in a much larger mill/drill. Not as
          accurate
          > but this 2 HP unit is really good at taking off the material. The
          > mill/drill is a Grizzly too. I use it for bigger projects, or where I
          have
          > to mill stuff like stainless. I then would finish on the mini.
          >
          >
          >
          > BTW, why so slow on the mill if you were cutting aluminum?
          >
          >
          >
          > _____
          >
          > From: GrizHFMinimill@yahoogroups.com
          [mailto:GrizHFMinimill@yahoogroups.com]
          > On Behalf Of CLevinski
          > Sent: Saturday, May 11, 2013 1:49 PM
          > To: GrizHFMinimill@yahoogroups.com
          > Subject: [GrizHFMinimill] How would YOU do this?
          >
          >
          >
          >
          >
          >
          >
          >
          >
          >
          >
          >
          >
          > Hi,
          >
          > While I've done a number of small projects on my lathe, my mini-mill
          is
          > definitely underutilized. So I started a little project today that
          involves
          > taking a 1.150 x 1.850 inch piece of aluminum I had lying around, and
          sizing
          > it to make a widget. Only problem is that it was almost 1.500 inches
          thick,
          > and I need it to be 1.000 inches thick. So I thought, "Nah, I don't
          need to
          > use the band saw! I'll just mill that puppy down.". Almost 2 hours
          of
          > continuous milling later (while wearing hearing protection, because I
          > haven't made a belt drive conversion), it is now down to 1.250 inches.
          I'm
          > face milling with a 5/8 inch end mill, only engaging about 1/3 of the
          > diameter, never climb milling, and cutting in all four directions.
          > (Essentially cutting in a counter-clockwise rectangle.) I'm running
          the
          > mini-mill fairly slowly (maybe 600 RPM?, though I tried it nearer to
          900 RPM
          > and didn't pick up any noticeable benefit except for greater
          swarf-throwing
          > range). I tried cuts from .020 to .030 inches and settled on .025
          inches as
          > maximum material removal without excess noise.
          >
          > I have a fly cutter set (though I've never used it) but fly cutters
          are
          > primarily for finishing cuts, I understand, so I don't think that's
          the
          > solution.
          >
          > So my question; how would YOU more experienced guys do this? Is there
          a
          > technique I'm missing that would allow me to do this faster? Since
          this
          > isn't a finishing cut, could I use the full end mill width? That
          would
          > certainly speed up the process but I read that it's bad for the end
          mill
          > (specially a four-flute) since one side is conventional milling and
          the
          > other side is climb milling.
          >
          > And yes, if I can't find a better way, I'll probably go back to the
          band saw
          > and then make a couple of passes with the mill to finish the surface.
          >
          > Times like this, I wish I had a Bridgeport. But I don't think I'd be
          able
          > to carry it down the cellar steps... ;)
          >
          >
          > Thanks,
          > Charlie
          >
        • gerry waclawiak
          Hi Charlie, fast stock removal in roughing to size is not the strong point of the mini machines so take advantage of anything else you have that will do it
          Message 4 of 24 , May 11, 2013
            Hi Charlie,

            fast stock removal in roughing to size is not the strong point of the mini machines so take advantage of anything else you have that will do it quicker, hacksaws, bandsaws, angle grinders all come to mind.

            One of my hobbies is making small steam locomotives so a small bandsaw joined the minis to cut slices of bar stock as blanks for wheels as parting a 1-2" bar in the lathe isn't fast or fun and it also gets a lot of use for other stock now.

            If you want to remove a reasonable amount of material in the mill you might want to consider investing in a roughing end mill. These are similar to normal end mills but the cutting edges are serrated like a bread knife so they remove chunks or material quite quickly and you then change to a normal mill for finishing.

            A fly cutter can also remove material quite quickly but this can expose one of the major weaknesses of the mini-mills, breakage of the plastic gears (there are now models with metal) which are very vulnerable to shock loads from intermittent cuts or the dreaded head drop. another weakness. The latter is really most commonly caused by poor technique or set up and forgetting to lock the head and table gibs.

            It is quite posibble to succesfully fly cut with a standard mill (I did it for quite a few years without problem) but you have to be very careful and diligent.

            A belt drive conversion really does transform the mill in several ways and I would recommend it to anyone, especially for fly cutting as it makes it a far nicer and more productive experience as you can be a little bolder in feed and cuts. The belt acts as a safety valve and an mistake will lead to slippage of the belt not the crunch of breaking gears You can of course make your own using you lathe and mill as I did.

            My fly cutters get a lot of use nowadays as I acquire a lot of my material as scrap to save money and it goes into the stock box awaiting a project and I end up roughing a fair bit to size if I have nothing exact or close suitable.

            Gerry W
            Leeds UK






            To: GrizHFMinimill@yahoogroups.com
            From: clevinski@...
            Date: Sat, 11 May 2013 20:48:46 +0000
            Subject: [GrizHFMinimill] How would YOU do this?

             
            Hi,

            While I've done a number of small projects on my lathe, my mini-mill is definitely underutilized.  So I started a little project today that involves taking a 1.150 x 1.850 inch piece of aluminum I had lying around, and sizing it to make a widget.  Only problem is that it was almost 1.500 inches thick, and I need it to be 1.000 inches thick.  So I thought, "Nah, I don't need to use the band saw!  I'll just mill that puppy down.".  Almost 2 hours of continuous milling later (while wearing hearing protection, because I haven't made a belt drive conversion), it is now down to 1.250 inches.  I'm face milling with a 5/8 inch end mill, only engaging about 1/3 of the diameter, never climb milling, and cutting in all four directions.  (Essentially cutting in a counter-clockwise rectangle.)  I'm running the mini-mill fairly slowly (maybe 600 RPM?, though I tried it nearer to 900 RPM and didn't pick up any noticeable benefit except for greater swarf-throwing range).  I tried cuts from .020 to .030 inches and settled on .025 inches as maximum material removal without excess noise.

            I have a fly cutter set (though I've never used it) but fly cutters are primarily for finishing cuts, I understand, so I don't think that's the solution.

            So my question; how would YOU more experienced guys do this?  Is there a technique I'm missing that would allow me to do this faster?  Since this isn't a finishing cut, could I use the full end mill width?  That would certainly speed up the process but I read that it's bad for the end mill (specially a four-flute) since one side is conventional milling and the other side is climb milling.

            And yes, if I can't find a better way, I'll probably go back to the band saw and then make a couple of passes with the mill to finish the surface.

            Times like this, I wish I had a Bridgeport.  But I don't think I'd be able to carry it down the cellar steps... ;)

            Thanks,
            Charlie


          • gerry waclawiak
            Hi Charlie, continuing along Ben s route the easiest thing is just to buy your widget but that rather defeats the object or hobby machining for fun, A little
            Message 5 of 24 , May 11, 2013
              Hi Charlie,
               
              continuing along Ben's route the easiest thing is just to buy your widget but that rather defeats the object or hobby machining for fun,

              A little less along the route you could also buy stock of the correct nominal size to make life easier but again you lose the thrill of crafting and shaping to what you want.

              Sometimes I think it would be nice to have the money to buy all the bigger top quality tools I would like and have a nice big workshop to keep them in but the reality is rather different and you have to compromise somewhere.

              I know we all differ but I get a great deal of satisfaction from improving and looking after my machines and in making the best use of what I have which make a succesful project all the sweeter.

              Gerry W
              Leeds UK




              To: GrizHFMinimill@yahoogroups.com
              From: clevinski@...
              Date: Sat, 11 May 2013 22:11:51 +0000
              Subject: [GrizHFMinimill] Re: How would YOU do this?

               
              Hi, Ben,

              Well, as much as I like your solution (bigger is always better and all
              that), it does seem to be kind of pricey to make a little part I could
              probably buy for $25 if I didn't want a project to build.

              Good point regarding the speed... I guess it calculates to around 1900
              RPM, at least by my rule of thumb. Maybe I'll try a speed in that range
              when I resume and see if it cuts my time significantly.

              Thanks,
              Charlie

              --- In GrizHFMinimill@yahoogroups.com, "Benjamin Bucceri" wrote:
              >
              > Well, you raise a good point with your widget project. What I would
              do, and
              > what I have done, is invest in a much larger mill/drill. Not as
              accurate
              > but this 2 HP unit is really good at taking off the material. The
              > mill/drill is a Grizzly too. I use it for bigger projects, or where I
              have
              > to mill stuff like stainless. I then would finish on the mini.
              >
              >
              >
              > BTW, why so slow on the mill if you were cutting aluminum?
              >
              >
              >
              > _____
              >
              > From: GrizHFMinimill@yahoogroups.com
              [mailto:GrizHFMinimill@yahoogroups.com]
              > On Behalf Of CLevinski
              > Sent: Saturday, May 11, 2013 1:49 PM
              > To: GrizHFMinimill@yahoogroups.com
              > Subject: [GrizHFMinimill] How would YOU do this?
              >
              >
              >
              >
              >
              >
              >
              >
              >
              >
              >
              >
              >
              > Hi,
              >
              > While I've done a number of small projects on my lathe, my mini-mill
              is
              > definitely underutilized. So I started a little project today that
              involves
              > taking a 1.150 x 1.850 inch piece of aluminum I had lying around, and
              sizing
              > it to make a widget. Only problem is that it was almost 1.500 inches
              thick,
              > and I need it to be 1.000 inches thick. So I thought, "Nah, I don't
              need to
              > use the band saw! I'll just mill that puppy down.". Almost 2 hours
              of
              > continuous milling later (while wearing hearing protection, because I
              > haven't made a belt drive conversion), it is now down to 1.250 inches.
              I'm
              > face milling with a 5/8 inch end mill, only engaging about 1/3 of the
              > diameter, never climb milling, and cutting in all four directions.
              > (Essentially cutting in a counter-clockwise rectangle.) I'm running
              the
              > mini-mill fairly slowly (maybe 600 RPM?, though I tried it nearer to
              900 RPM
              > and didn't pick up any noticeable benefit except for greater
              swarf-throwing
              > range). I tried cuts from .020 to .030 inches and settled on .025
              inches as
              > maximum material removal without excess noise.
              >
              > I have a fly cutter set (though I've never used it) but fly cutters
              are
              > primarily for finishing cuts, I understand, so I don't think that's
              the
              > solution.
              >
              > So my question; how would YOU more experienced guys do this? Is there
              a
              > technique I'm missing that would allow me to do this faster? Since
              this
              > isn't a finishing cut, could I use the full end mill width? That
              would
              > certainly speed up the process but I read that it's bad for the end
              mill
              > (specially a four-flute) since one side is conventional milling and
              the
              > other side is climb milling.
              >
              > And yes, if I can't find a better way, I'll probably go back to the
              band saw
              > and then make a couple of passes with the mill to finish the surface.
              >
              > Times like this, I wish I had a Bridgeport. But I don't think I'd be
              able
              > to carry it down the cellar steps... ;)
              >
              >
              > Thanks,
              > Charlie
              >


            • CLevinski
              Thanks, guys... I m going to remove most of the excess stock some other way and use the mill for the finish dimension. Gerry, I thought you were limited to
              Message 6 of 24 , May 11, 2013
                Thanks, guys...

                I'm going to remove most of the excess stock some other way and use the
                mill for the finish dimension.

                Gerry, I thought you were limited to fairly light cuts with a fly
                cutter; is that not true? I guess one could be more aggressive in
                aluminum, of course.

                I've recently become interested in steam engines (not necessarily
                locomotives, though my first real job was for a hobby company where we
                designed, built and sold model train controls) and was considering, once
                I gained a little more expertise, buying of the the small kits.

                Thanks again to all,
                Charlie


                --- In GrizHFMinimill@yahoogroups.com, gerry waclawiak wrote:
                >
                > Hi Charlie,
                >
                > fast stock removal in roughing to size is not the strong point of the
                mini machines so take advantage of anything else you have that will do
                it quicker, hacksaws, bandsaws, angle grinders all come to mind.
                >
                > One of my hobbies is making small steam locomotives so a small bandsaw
                joined the minis to cut slices of bar stock as blanks for wheels as
                parting a 1-2" bar in the lathe isn't fast or fun and it also gets a lot
                of use for other stock now.
                >
                > If you want to remove a reasonable amount of material in the mill you
                might want to consider investing in a roughing end mill. These are
                similar to normal end mills but the cutting edges are serrated like a
                bread knife so they remove chunks or material quite quickly and you then
                change to a normal mill for finishing.
                >
                > A fly cutter can also remove material quite quickly but this can
                expose one of the major weaknesses of the mini-mills, breakage of the
                plastic gears (there are now models with metal) which are very
                vulnerable to shock loads from intermittent cuts or the dreaded head
                drop. another weakness. The latter is really most commonly caused by
                poor technique or set up and forgetting to lock the head and table gibs.
                >
                > It is quite posibble to succesfully fly cut with a standard mill (I
                did it for quite a few years without problem) but you have to be very
                careful and diligent.
                >
                > A belt drive conversion really does transform the mill in several ways
                and I would recommend it to anyone, especially for fly cutting as it
                makes it a far nicer and more productive experience as you can be a
                little bolder in feed and cuts. The belt acts as a safety valve and an
                mistake will lead to slippage of the belt not the crunch of breaking
                gears You can of course make your own using you lathe and mill as I did.
                >
                > My fly cutters get a lot of use nowadays as I acquire a lot of my
                material as scrap to save money and it goes into the stock box awaiting
                a project and I end up roughing a fair bit to size if I have nothing
                exact or close suitable.
                >
                > Gerry W
                > Leeds UK
                >
                >
                >
                > To: GrizHFMinimill@yahoogroups.com
                > From: clevinski@...
                > Date: Sat, 11 May 2013 20:48:46 +0000
                > Subject: [GrizHFMinimill] How would YOU do this?
                >
                >
                >
                >
                >
                >
                >
                >
                >
                >
                >
                >
                >
                >
                >
                >
                >
                >
                >
                >
                >
                >
                >
                >
                >
                >
                > Hi,
                >
                > While I've done a number of small projects on my lathe, my mini-mill
                is definitely underutilized. So I started a little project today that
                involves taking a 1.150 x 1.850 inch piece of aluminum I had lying
                around, and sizing it to make a widget. Only problem is that it was
                almost 1.500 inches thick, and I need it to be 1.000 inches thick. So I
                thought, "Nah, I don't need to use the band saw! I'll just mill that
                puppy down.". Almost 2 hours of continuous milling later (while wearing
                hearing protection, because I haven't made a belt drive conversion), it
                is now down to 1.250 inches. I'm face milling with a 5/8 inch end mill,
                only engaging about 1/3 of the diameter, never climb milling, and
                cutting in all four directions. (Essentially cutting in a
                counter-clockwise rectangle.) I'm running the mini-mill fairly slowly
                (maybe 600 RPM?, though I tried it nearer to 900 RPM and didn't pick up
                any noticeable benefit except for greater swarf-throwing range). I
                tried cuts from .020 to .030 inches and settled on .025 inches as
                maximum material removal without excess noise.
                >
                > I have a fly cutter set (though I've never used it) but fly cutters
                are primarily for finishing cuts, I understand, so I don't think that's
                the solution.
                >
                > So my question; how would YOU more experienced guys do this? Is there
                a technique I'm missing that would allow me to do this faster? Since
                this isn't a finishing cut, could I use the full end mill width? That
                would certainly speed up the process but I read that it's bad for the
                end mill (specially a four-flute) since one side is conventional milling
                and the other side is climb milling.
                >
                > And yes, if I can't find a better way, I'll probably go back to the
                band saw and then make a couple of passes with the mill to finish the
                surface.
                >
                > Times like this, I wish I had a Bridgeport. But I don't think I'd be
                able to carry it down the cellar steps...
                >
                > Thanks,
                > Charlie
                >
              • SirJohnOfYork
                If you go to: http://www.cdcotools.com/ and click the Cutting Tools tab near the top of the page, and then click _End Mills, Indexible End Mills & Face
                Message 7 of 24 , May 11, 2013
                   If you go to:
                  http://www.cdcotools.com/
                  and click the "Cutting Tools" tab near the top of the page, and then click "End Mills, Indexible End Mills & Face Milling Cutters" from the page that comes up, the very first items at the top of the next page are the "roughing end mills." I'd suggest the 3/8" and 1/2" sizes for general purpose, smaller if needed. If you click the picture of the roughing end mill on the left side of the page, you will get a much larger image to look at, and you can then see how the roughing end mill has nasty little "teeth" all the way up and down the flutes. They say roughing they mean roughing, as those "teeth" leave a really rough finish, grooved kind of like a plowed field, but are pretty good for taking deeper cuts than you can normally get away with using typical standard HSS or indexible carbide end mills, at least on these little X2 mini-mills. Note that the 3/8" end mill is only $7 and the 1/2" is $10, so you wouldn't be making a huge investment in any case. I use mine.

                   Cheers,
                   John Z.

                  On 5/11/2013 4:48 PM, CLevinski wrote:
                   

                  Hi,

                  While I've done a number of small projects on my lathe, my mini-mill is definitely underutilized.  So I started a little project today that involves taking a 1.150 x 1.850 inch piece of aluminum I had lying around, and sizing it to make a widget.  Only problem is that it was almost 1.500 inches thick, and I need it to be 1.000 inches thick.  So I thought, "Nah, I don't need to use the band saw!  I'll just mill that puppy down.".  Almost 2 hours of continuous milling later (while wearing hearing protection, because I haven't made a belt drive conversion), it is now down to 1.250 inches.  I'm face milling with a 5/8 inch end mill, only engaging about 1/3 of the diameter, never climb milling, and cutting in all four directions.  (Essentially cutting in a counter-clockwise rectangle.)  I'm running the mini-mill fairly slowly (maybe 600 RPM?, though I tried it nearer to 900 RPM and didn't pick up any noticeable benefit except for greater swarf-throwing range).  I tried cuts from .020 to .030 inches and settled on .025 inches as maximum material removal without excess noise.

                  I have a fly cutter set (though I've never used it) but fly cutters are primarily for finishing cuts, I understand, so I don't think that's the solution.

                  So my question; how would YOU more experienced guys do this?  Is there a technique I'm missing that would allow me to do this faster?  Since this isn't a finishing cut, could I use the full end mill width?  That would certainly speed up the process but I read that it's bad for the end mill (specially a four-flute) since one side is conventional milling and the other side is climb milling.

                  And yes, if I can't find a better way, I'll probably go back to the band saw and then make a couple of passes with the mill to finish the surface.

                  Times like this, I wish I had a Bridgeport.  But I don't think I'd be able to carry it down the cellar steps...

                  Thanks,
                  Charlie


                • CLevinski
                  Thanks, John... I m going to do that so I have options for next time... Thanks, Charlie ... the ... are ... mill ... X2 ... $10, ... that ... So ... (while ...
                  Message 8 of 24 , May 11, 2013
                    Thanks, John...

                    I'm going to do that so I have options for next time...

                    Thanks,
                    Charlie


                    --- In GrizHFMinimill@yahoogroups.com, SirJohnOfYork wrote:
                    >
                    > If you go to:
                    > http://www.cdcotools.com/
                    > and click the "Cutting Tools" tab near the top of the page, and then
                    > click "_End Mills, Indexible End Mills & Face Milling Cutters_" from
                    the
                    > page that comes up, the very first items at the top of the next page
                    are
                    > the "roughing end mills." I'd suggest the 3/8" and 1/2" sizes for
                    > general purpose, smaller if needed. If you click the picture of the
                    > roughing end mill on the left side of the page, you will get a much
                    > larger image to look at, and you can then see how the roughing end
                    mill
                    > has nasty little "teeth" all the way up and down the flutes. They say
                    > roughing they mean roughing, as those "teeth" leave a really rough
                    > finish, grooved kind of like a plowed field, but are pretty good for
                    > taking deeper cuts than you can normally get away with using typical
                    > standard HSS or indexible carbide end mills, at least on these little
                    X2
                    > mini-mills. Note that the 3/8" end mill is only $7 and the 1/2" is
                    $10,
                    > so you wouldn't be making a huge investment in any case. I use mine.
                    >
                    > Cheers,
                    > John Z.
                    >
                    > On 5/11/2013 4:48 PM, CLevinski wrote:
                    > >
                    > > Hi,
                    > >
                    > > While I've done a number of small projects on my lathe, my mini-mill
                    > > is definitely underutilized. So I started a little project today
                    that
                    > > involves taking a 1.150 x 1.850 inch piece of aluminum I had lying
                    > > around, and sizing it to make a widget. Only problem is that it was
                    > > almost 1.500 inches thick, and I need it to be 1.000 inches thick.
                    So
                    > > I thought, "Nah, I don't need to use the band saw! I'll just mill
                    > > that puppy down.". Almost 2 hours of continuous milling later
                    (while
                    > > wearing hearing protection, because I haven't made a belt drive
                    > > conversion), it is now down to 1.250 inches. I'm face milling with
                    a
                    > > 5/8 inch end mill, only engaging about 1/3 of the diameter, never
                    > > climb milling, and cutting in all four directions. (Essentially
                    > > cutting in a counter-clockwise rectangle.) I'm running the
                    mini-mill
                    > > fairly slowly (maybe 600 RPM?, though I tried it nearer to 900 RPM
                    and
                    > > didn't pick up any noticeable benefit except for greater
                    > > swarf-throwing range). I tried cuts from .020 to .030 inches and
                    > > settled on .025 inches as maximum material removal without excess
                    noise.
                    > >
                    > > I have a fly cutter set (though I've never used it) but fly cutters
                    > > are primarily for finishing cuts, I understand, so I don't *think*
                    > > that's the solution.
                    > >
                    > > So my question; how would YOU more experienced guys do this? Is
                    there
                    > > a technique I'm missing that would allow me to do this faster?
                    Since
                    > > this isn't a finishing cut, could I use the full end mill width?
                    That
                    > > would certainly speed up the process but I read that it's bad for
                    the
                    > > end mill (specially a four-flute) since one side is conventional
                    > > milling and the other side is climb milling.
                    > >
                    > > And yes, if I can't find a better way, I'll probably go back to the
                    > > band saw and then make a couple of passes with the mill to finish
                    the
                    > > surface.
                    > >
                    > > Times like this, I wish I had a Bridgeport. But I don't think I'd
                    be
                    > > able to carry it down the cellar steps... ;)
                    > >
                    > > Thanks,
                    > > Charlie
                    > >
                    >
                  • Robert Furmanak
                    Charlie My experience is that the Mini Mill is not nearly stiff enough to use a 5/8 end mill. It does not matter that you are only using 1/3 of the diameter,
                    Message 9 of 24 , May 11, 2013

                      Charlie

                       

                      My experience is that the Mini Mill is not nearly stiff enough to use a 5/8 end mill.  It does not matter that you are only using 1/3 of the diameter, what matters is that you are putting a considerable side load on the machine with every pass the cutting edge makes.  I’m willing to bet you would make twice as much progress with a 3/8 end mill.  Also, I have found that even with the smaller end mill, there is far less vibration when using the full width of the end mill, rather than the side.  Here is how I would handle your problem.  Use a 3/8 end mill, and make 3/8 wide cuts.  I think you will find that the machine is quietest when the end mill has a large contact area with the material being cut.  The reason is that there are always at least two flutes in contact with the material, while your method of using 1/3 the diameter likely has just one flute in contact, creating an alternating cycle of high loads going to near zero load, and back.

                       

                      As for climb milling, I think that has been given a bad rap.  I read a good paper on the physics of it a while ago, and climb milling is actually less stressful to the cutting edge.  The problem arises when the machine is too loose, and allows the end mill to pull itself deeper into the material.  I do all my finishing cuts as climbing cuts, and I have my machine set very tight.   When using the full width of the end mill as I suggested above, the climbing forces are held in check by the resistance the other side is experiencing.  However, with very small end mills, the mill will try to climb sideways by bending, so one has to watch for that, at 1/8 inch diameter and below.  

                       

                      Robert

                       

                      From: GrizHFMinimill@yahoogroups.com [mailto:GrizHFMinimill@yahoogroups.com] On Behalf Of CLevinski
                      Sent: Saturday, May 11, 2013 4:49 PM
                      To: GrizHFMinimill@yahoogroups.com
                      Subject: [GrizHFMinimill] How would YOU do this?

                       

                       

                      Hi,

                      While I've done a number of small projects on my lathe, my mini-mill is definitely underutilized.  So I started a little project today that involves taking a 1.150 x 1.850 inch piece of aluminum I had lying around, and sizing it to make a widget.  Only problem is that it was almost 1.500 inches thick, and I need it to be 1.000 inches thick.  So I thought, "Nah, I don't need to use the band saw!  I'll just mill that puppy down.".  Almost 2 hours of continuous milling later (while wearing hearing protection, because I haven't made a belt drive conversion), it is now down to 1.250 inches.  I'm face milling with a 5/8 inch end mill, only engaging about 1/3 of the diameter, never climb milling, and cutting in all four directions.  (Essentially cutting in a counter-clockwise rectangle.)  I'm running the mini-mill fairly slowly (maybe 600 RPM?, though I tried it nearer to 900 RPM and didn't pick up any noticeable benefit except for greater swarf-throwing range).  I tried cuts from .020 to .030 inches and settled on .025 inches as maximum material removal without excess noise.

                      I have a fly cutter set (though I've never used it) but fly cutters are primarily for finishing cuts, I understand, so I don't think that's the solution.

                      So my question; how would YOU more experienced guys do this?  Is there a technique I'm missing that would allow me to do this faster?  Since this isn't a finishing cut, could I use the full end mill width?  That would certainly speed up the process but I read that it's bad for the end mill (specially a four-flute) since one side is conventional milling and the other side is climb milling.

                      And yes, if I can't find a better way, I'll probably go back to the band saw and then make a couple of passes with the mill to finish the surface.

                      Times like this, I wish I had a Bridgeport.  But I don't think I'd be able to carry it down the cellar steps... ;)

                      Thanks,
                      Charlie

                    • Goran Hosinsky
                      Hello Robert, How deep would you go each pass with the 3/8 mill? Goran, Canary Islands
                      Message 10 of 24 , May 12, 2013
                        Hello Robert,

                        How deep would you go each pass with the 3/8 mill?

                        Goran, Canary Islands

                        On 2013-05-12 03:35, Robert Furmanak wrote:
                         

                        Charlie

                         

                        My experience is that the Mini Mill is not nearly stiff enough to use a 5/8 end mill.  It does not matter that you are only using 1/3 of the diameter, what matters is that you are putting a considerable side load on the machine with every pass the cutting edge makes.  I’m willing to bet you would make twice as much progress with a 3/8 end mill.  Also, I have found that even with the smaller end mill, there is far less vibration when using the full width of the end mill, rather than the side.  Here is how I would handle your problem.  Use a 3/8 end mill, and make 3/8 wide cuts.  I think you will find that the machine is quietest when the end mill has a large contact area with the material being cut.  The reason is that there are always at least two flutes in contact with the material, while your method of using 1/3 the diameter likely has just one flute in contact, creating an alternating cycle of high loads going to near zero load, and back.

                         

                        As for climb milling, I think that has been given a bad rap.  I read a good paper on the physics of it a while ago, and climb milling is actually less stressful to the cutting edge.  The problem arises when the machine is too loose, and allows the end mill to pull itself deeper into the material.  I do all my finishing cuts as climbing cuts, and I have my machine set very tight.   When using the full width of the end mill as I suggested above, the climbing forces are held in check by the resistance the other side is experiencing.  However, with very small end mills, the mill will try to climb sideways by bending, so one has to watch for that, at 1/8 inch diameter and below.  

                         

                        Robert

                         

                        From: GrizHFMinimill@yahoogroups.com [mailto:GrizHFMinimill@yahoogroups.com] On Behalf Of CLevinski
                        Sent: Saturday, May 11, 2013 4:49 PM
                        To: GrizHFMinimill@yahoogroups.com
                        Subject: [GrizHFMinimill] How would YOU do this?

                         

                         

                        Hi,

                        While I've done a number of small projects on my lathe, my mini-mill is definitely underutilized.  So I started a little project today that involves taking a 1.150 x 1.850 inch piece of aluminum I had lying around, and sizing it to make a widget.  Only problem is that it was almost 1.500 inches thick, and I need it to be 1.000 inches thick.  So I thought, "Nah, I don't need to use the band saw!  I'll just mill that puppy down.".  Almost 2 hours of continuous milling later (while wearing hearing protection, because I haven't made a belt drive conversion), it is now down to 1.250 inches.  I'm face milling with a 5/8 inch end mill, only engaging about 1/3 of the diameter, never climb milling, and cutting in all four directions.  (Essentially cutting in a counter-clockwise rectangle.)  I'm running the mini-mill fairly slowly (maybe 600 RPM?, though I tried it nearer to 900 RPM and didn't pick up any noticeable benefit except for greater swarf-throwing range).  I tried cuts from .020 to .030 inches and settled on .025 inches as maximum material removal without excess noise.

                        I have a fly cutter set (though I've never used it) but fly cutters are primarily for finishing cuts, I understand, so I don't think that's the solution.

                        So my question; how would YOU more experienced guys do this?  Is there a technique I'm missing that would allow me to do this faster?  Since this isn't a finishing cut, could I use the full end mill width?  That would certainly speed up the process but I read that it's bad for the end mill (specially a four-flute) since one side is conventional milling and the other side is climb milling.

                        And yes, if I can't find a better way, I'll probably go back to the band saw and then make a couple of passes with the mill to finish the surface.

                        Times like this, I wish I had a Bridgeport.  But I don't think I'd be able to carry it down the cellar steps... ;)

                        Thanks,
                        Charlie


                      • gerry waclawiak
                        Hi Charlie, Personally I think that fly cutters get a bad press in mini-mill circles mainly due to some peoples bad experience with breaking the gears through
                        Message 11 of 24 , May 12, 2013
                          Hi Charlie,
                          Personally I think that fly cutters get a bad press in mini-mill circles mainly due to some peoples bad experience with breaking the gears through careless use or bad practice.

                          The plastic gears are not the best for shock loading through intermittent cutting or a dig in through head drop or excess feed and give little or no warning to the user although to be fair the original design was as a small hobby drill/mill and I don't really think they really envisaged the use or fly cutters and the like.

                          The latest belt drive versions (and belt mods) really do make a big difference to usability and capability.

                          Whilst it is true that the cuts with a fly cutter on a mini need to be light (lack of power is an issue if not the gears) they score very highly on the area cut in a single pass so will remove material a lot quicker than say the 5/8" cutter you used.

                          This is especially true in softer materials such as brass, aluminium (aluminum to you guys), or plastics and larger sections.

                          I attended one of the UK's premier Model Engineering shows on Friday and acquired several discs approx 3.5" dia x 7/8" thick of glass filled nylon for the equivalent of a few bucks (bar ends scrap from a CNC machining company) the diameter being consistent but thickness varying maybe 1/8".

                          Using a 1/8" fly cutter with a 3.5" sweep I was able to flatten both sides and regularise the thickness of 8 discs in less than 1.5hrs with perhaps 5 single passes per disc in about 1.5hrs total. Using a 5/8" end mill I could probably have regularised the thickness in 3 passes but would require 7 passes each time to cover the same area (5/8" x7 =3.5") so over 4x the table movement. The mill would also have left tramlines from the seven passes per side rather then the single smooth sweep of the fly cutter

                          Another thing to consider is that of the cost of cutters. The fly cutter I used had a single 4" length of 1/8" square HSS (basic lathe tool stock) suitably sharpened quickly and easily on a bench grinder and resharpen-able dozens if not hundreds of times, cost a couple of dollars. A single disposable end mill would cost severable dollars and cannot easily be home sharpened.

                          If you like the idea of live steam engines(most of which will run well on a few PSI of compressed air or even lung power) you might like to consider some of the simple internet "wobbler" designs made from  a few dollars worth of scrap bar-stock rather than a kit. Quick and easy to make, great fun and good practice for the lathe and mill skills

                          Gerry W
                          leeds UK



                          To: GrizHFMinimill@yahoogroups.com
                          From: clevinski@...
                          Date: Sun, 12 May 2013 00:03:05 +0000
                          Subject: [GrizHFMinimill] Re: How would YOU do this?

                           
                          Thanks, guys...

                          I'm going to remove most of the excess stock some other way and use the
                          mill for the finish dimension.

                          Gerry, I thought you were limited to fairly light cuts with a fly
                          cutter; is that not true? I guess one could be more aggressive in
                          aluminum, of course.

                          I've recently become interested in steam engines (not necessarily
                          locomotives, though my first real job was for a hobby company where we
                          designed, built and sold model train controls) and was considering, once
                          I gained a little more expertise, buying of the the small kits.

                          Thanks again to all,
                          Charlie

                          --- In GrizHFMinimill@yahoogroups.com, gerry waclawiak wrote:
                          >
                          > Hi Charlie,
                          >
                          > fast stock removal in roughing to size is not the strong point of the
                          mini machines so take advantage of anything else you have that will do
                          it quicker, hacksaws, bandsaws, angle grinders all come to mind.
                          >
                          > One of my hobbies is making small steam locomotives so a small bandsaw
                          joined the minis to cut slices of bar stock as blanks for wheels as
                          parting a 1-2" bar in the lathe isn't fast or fun and it also gets a lot
                          of use for other stock now.
                          >
                          > If you want to remove a reasonable amount of material in the mill you
                          might want to consider investing in a roughing end mill. These are
                          similar to normal end mills but the cutting edges are serrated like a
                          bread knife so they remove chunks or material quite quickly and you then
                          change to a normal mill for finishing.
                          >
                          > A fly cutter can also remove material quite quickly but this can
                          expose one of the major weaknesses of the mini-mills, breakage of the
                          plastic gears (there are now models with metal) which are very
                          vulnerable to shock loads from intermittent cuts or the dreaded head
                          drop. another weakness. The latter is really most commonly caused by
                          poor technique or set up and forgetting to lock the head and table gibs.
                          >
                          > It is quite posibble to succesfully fly cut with a standard mill (I
                          did it for quite a few years without problem) but you have to be very
                          careful and diligent.
                          >
                          > A belt drive conversion really does transform the mill in several ways
                          and I would recommend it to anyone, especially for fly cutting as it
                          makes it a far nicer and more productive experience as you can be a
                          little bolder in feed and cuts. The belt acts as a safety valve and an
                          mistake will lead to slippage of the belt not the crunch of breaking
                          gears You can of course make your own using you lathe and mill as I did.
                          >
                          > My fly cutters get a lot of use nowadays as I acquire a lot of my
                          material as scrap to save money and it goes into the stock box awaiting
                          a project and I end up roughing a fair bit to size if I have nothing
                          exact or close suitable.
                          >
                          > Gerry W
                          > Leeds UK
                          >
                          >
                          >
                          > To: GrizHFMinimill@yahoogroups.com
                          > From: clevinski@...
                          > Date: Sat, 11 May 2013 20:48:46 +0000
                          > Subject: [GrizHFMinimill] How would YOU do this?
                          >
                          >
                          >
                          >
                          >
                          >
                          >
                          >
                          >
                          >
                          >
                          >
                          >
                          >
                          >
                          >
                          >
                          >
                          >
                          >
                          >
                          >
                          >
                          >
                          >
                          >
                          > Hi,
                          >
                          > While I've done a number of small projects on my lathe, my mini-mill
                          is definitely underutilized. So I started a little project today that
                          involves taking a 1.150 x 1.850 inch piece of aluminum I had lying
                          around, and sizing it to make a widget. Only problem is that it was
                          almost 1.500 inches thick, and I need it to be 1.000 inches thick. So I
                          thought, "Nah, I don't need to use the band saw! I'll just mill that
                          puppy down.". Almost 2 hours of continuous milling later (while wearing
                          hearing protection, because I haven't made a belt drive conversion), it
                          is now down to 1.250 inches. I'm face milling with a 5/8 inch end mill,
                          only engaging about 1/3 of the diameter, never climb milling, and
                          cutting in all four directions. (Essentially cutting in a
                          counter-clockwise rectangle.) I'm running the mini-mill fairly slowly
                          (maybe 600 RPM?, though I tried it nearer to 900 RPM and didn't pick up
                          any noticeable benefit except for greater swarf-throwing range). I
                          tried cuts from .020 to .030 inches and settled on .025 inches as
                          maximum material removal without excess noise.
                          >
                          > I have a fly cutter set (though I've never used it) but fly cutters
                          are primarily for finishing cuts, I understand, so I don't think that's
                          the solution.
                          >
                          > So my question; how would YOU more experienced guys do this? Is there
                          a technique I'm missing that would allow me to do this faster? Since
                          this isn't a finishing cut, could I use the full end mill width? That
                          would certainly speed up the process but I read that it's bad for the
                          end mill (specially a four-flute) since one side is conventional milling
                          and the other side is climb milling.
                          >
                          > And yes, if I can't find a better way, I'll probably go back to the
                          band saw and then make a couple of passes with the mill to finish the
                          surface.
                          >
                          > Times like this, I wish I had a Bridgeport. But I don't think I'd be
                          able to carry it down the cellar steps...
                          >
                          > Thanks,
                          > Charlie
                          >


                        • Robert Furmanak
                          Goran, I don t have a good answer for that. I have tried both deeper cuts, maybe 0,75 mm while going slower, and about 0,25 mm while going faster. A lot
                          Message 12 of 24 , May 12, 2013

                            Goran,

                             

                              I don’t have a good answer for that.  I have tried both deeper cuts, maybe 0,75 mm while going slower, and about 0,25 mm while going faster.  A lot depends on your machine.  I started out with the original  small table mini mill, then converted it to a large table mill.  There is a big difference in rigidity between the two tables, making it possible to take deeper cuts on the large table.  Now I have converted my machine to a solid column, and can take even deeper cuts safely.  But I just completed the conversion two weeks ago, and have not used it enough yet to give you a good answer.

                            When taking deep cuts, I often lock the axis that is not moving.  Anything you can do to increase stiffness helps.

                            I also normally use carbide end mills, which can be run faster, but I would not recommend them for inexperienced users.  They are extremely sharp, which is good, but also extremely brittle.  Vibration puts high shock loads on the cutting edge, and can chip it.  I went through a lot of carbide in my early days.   Now I have a better feel for the limitations of carbide, and my upgraded machine is now better suited for it.  So, finally after a couple of years, I’m getting decent lifetimes from my carbide bits, and they usually don’t fail unless I do something stupid like let it fall out of the collet and land face down on the table.   That usually results in a worthless end mill.

                             

                            Robert

                             

                            From: GrizHFMinimill@yahoogroups.com [mailto:GrizHFMinimill@yahoogroups.com] On Behalf Of Goran Hosinsky
                            Sent: Sunday, May 12, 2013 3:29 AM
                            To: GrizHFMinimill@yahoogroups.com
                            Subject: Re: [GrizHFMinimill] How would YOU do this?

                             

                             

                            Hello Robert,

                            How deep would you go each pass with the 3/8 mill?

                            Goran, Canary Islands

                            On 2013-05-12 03:35, Robert Furmanak wrote:

                             

                            Charlie

                             

                            My experience is that the Mini Mill is not nearly stiff enough to use a 5/8 end mill.  It does not matter that you are only using 1/3 of the diameter, what matters is that you are putting a considerable side load on the machine with every pass the cutting edge makes.  I’m willing to bet you would make twice as much progress with a 3/8 end mill.  Also, I have found that even with the smaller end mill, there is far less vibration when using the full width of the end mill, rather than the side.  Here is how I would handle your problem.  Use a 3/8 end mill, and make 3/8 wide cuts.  I think you will find that the machine is quietest when the end mill has a large contact area with the material being cut.  The reason is that there are always at least two flutes in contact with the material, while your method of using 1/3 the diameter likely has just one flute in contact, creating an alternating cycle of high loads going to near zero load, and back.

                             

                            As for climb milling, I think that has been given a bad rap.  I read a good paper on the physics of it a while ago, and climb milling is actually less stressful to the cutting edge.  The problem arises when the machine is too loose, and allows the end mill to pull itself deeper into the material.  I do all my finishing cuts as climbing cuts, and I have my machine set very tight.   When using the full width of the end mill as I suggested above, the climbing forces are held in check by the resistance the other side is experiencing.  However, with very small end mills, the mill will try to climb sideways by bending, so one has to watch for that, at 1/8 inch diameter and below.  

                             

                            Robert

                             

                            From: GrizHFMinimill@yahoogroups.com [mailto:GrizHFMinimill@yahoogroups.com] On Behalf Of CLevinski
                            Sent: Saturday, May 11, 2013 4:49 PM
                            To: GrizHFMinimill@yahoogroups.com
                            Subject: [GrizHFMinimill] How would YOU do this?

                             

                             

                            Hi,

                            While I've done a number of small projects on my lathe, my mini-mill is definitely underutilized.  So I started a little project today that involves taking a 1.150 x 1.850 inch piece of aluminum I had lying around, and sizing it to make a widget.  Only problem is that it was almost 1.500 inches thick, and I need it to be 1.000 inches thick.  So I thought, "Nah, I don't need to use the band saw!  I'll just mill that puppy down.".  Almost 2 hours of continuous milling later (while wearing hearing protection, because I haven't made a belt drive conversion), it is now down to 1.250 inches.  I'm face milling with a 5/8 inch end mill, only engaging about 1/3 of the diameter, never climb milling, and cutting in all four directions.  (Essentially cutting in a counter-clockwise rectangle.)  I'm running the mini-mill fairly slowly (maybe 600 RPM?, though I tried it nearer to 900 RPM and didn't pick up any noticeable benefit except for greater swarf-throwing range).  I tried cuts from .020 to .030 inches and settled on .025 inches as maximum material removal without excess noise.

                            I have a fly cutter set (though I've never used it) but fly cutters are primarily for finishing cuts, I understand, so I don't think that's the solution.

                            So my question; how would YOU more experienced guys do this?  Is there a technique I'm missing that would allow me to do this faster?  Since this isn't a finishing cut, could I use the full end mill width?  That would certainly speed up the process but I read that it's bad for the end mill (specially a four-flute) since one side is conventional milling and the other side is climb milling.

                            And yes, if I can't find a better way, I'll probably go back to the band saw and then make a couple of passes with the mill to finish the surface.

                            Times like this, I wish I had a Bridgeport.  But I don't think I'd be able to carry it down the cellar steps... ;)

                            Thanks,
                            Charlie

                             

                          • CLevinski
                            Hi, Robert, That s some very useful information. I would actually cut more material with a full with 3/8 inch end mill than a 1/3 width 5/8 inch end mill, so
                            Message 13 of 24 , May 12, 2013
                              Hi, Robert,

                              That's some very useful information. I would actually cut more material
                              with a full with 3/8 inch end mill than a 1/3 width 5/8 inch end mill,
                              so that would speed things up. Your observations about the vibration
                              make sense, so I'm going to give it a try. But either way, I'm better
                              off to cut out as much stock as I can with other methods first.

                              Many thanks,
                              Charlie


                              --- In GrizHFMinimill@yahoogroups.com, "Robert Furmanak" wrote:
                              >
                              > Charlie
                              >
                              >
                              >
                              > My experience is that the Mini Mill is not nearly stiff enough to use
                              a 5/8
                              > end mill. It does not matter that you are only using 1/3 of the
                              diameter,
                              > what matters is that you are putting a considerable side load on the
                              machine
                              > with every pass the cutting edge makes. I'm willing to bet you would
                              make
                              > twice as much progress with a 3/8 end mill. Also, I have found that
                              even
                              > with the smaller end mill, there is far less vibration when using the
                              full
                              > width of the end mill, rather than the side. Here is how I would
                              handle
                              > your problem. Use a 3/8 end mill, and make 3/8 wide cuts. I think
                              you will
                              > find that the machine is quietest when the end mill has a large
                              contact area
                              > with the material being cut. The reason is that there are always at
                              least
                              > two flutes in contact with the material, while your method of using
                              1/3 the
                              > diameter likely has just one flute in contact, creating an alternating
                              cycle
                              > of high loads going to near zero load, and back.
                              >
                              >
                              >
                              > As for climb milling, I think that has been given a bad rap. I read a
                              good
                              > paper on the physics of it a while ago, and climb milling is actually
                              less
                              > stressful to the cutting edge. The problem arises when the machine is
                              too
                              > loose, and allows the end mill to pull itself deeper into the
                              material. I
                              > do all my finishing cuts as climbing cuts, and I have my machine set
                              very
                              > tight. When using the full width of the end mill as I suggested
                              above, the
                              > climbing forces are held in check by the resistance the other side is
                              > experiencing. However, with very small end mills, the mill will try
                              to
                              > climb sideways by bending, so one has to watch for that, at 1/8 inch
                              > diameter and below.
                              >
                              >
                              >
                              > Robert
                              >
                              >
                              >
                              > From: GrizHFMinimill@yahoogroups.com
                              [mailto:GrizHFMinimill@yahoogroups.com]
                              > On Behalf Of CLevinski
                              > Sent: Saturday, May 11, 2013 4:49 PM
                              > To: GrizHFMinimill@yahoogroups.com
                              > Subject: [GrizHFMinimill] How would YOU do this?
                              >
                              >
                              >
                              >
                              >
                              > Hi,
                              >
                              > While I've done a number of small projects on my lathe, my mini-mill
                              is
                              > definitely underutilized. So I started a little project today that
                              involves
                              > taking a 1.150 x 1.850 inch piece of aluminum I had lying around, and
                              sizing
                              > it to make a widget. Only problem is that it was almost 1.500 inches
                              thick,
                              > and I need it to be 1.000 inches thick. So I thought, "Nah, I don't
                              need to
                              > use the band saw! I'll just mill that puppy down.". Almost 2 hours
                              of
                              > continuous milling later (while wearing hearing protection, because I
                              > haven't made a belt drive conversion), it is now down to 1.250 inches.
                              I'm
                              > face milling with a 5/8 inch end mill, only engaging about 1/3 of the
                              > diameter, never climb milling, and cutting in all four directions.
                              > (Essentially cutting in a counter-clockwise rectangle.) I'm running
                              the
                              > mini-mill fairly slowly (maybe 600 RPM?, though I tried it nearer to
                              900 RPM
                              > and didn't pick up any noticeable benefit except for greater
                              swarf-throwing
                              > range). I tried cuts from .020 to .030 inches and settled on .025
                              inches as
                              > maximum material removal without excess noise.
                              >
                              > I have a fly cutter set (though I've never used it) but fly cutters
                              are
                              > primarily for finishing cuts, I understand, so I don't think that's
                              the
                              > solution.
                              >
                              > So my question; how would YOU more experienced guys do this? Is there
                              a
                              > technique I'm missing that would allow me to do this faster? Since
                              this
                              > isn't a finishing cut, could I use the full end mill width? That
                              would
                              > certainly speed up the process but I read that it's bad for the end
                              mill
                              > (specially a four-flute) since one side is conventional milling and
                              the
                              > other side is climb milling.
                              >
                              > And yes, if I can't find a better way, I'll probably go back to the
                              band saw
                              > and then make a couple of passes with the mill to finish the surface.
                              >
                              > Times like this, I wish I had a Bridgeport. But I don't think I'd be
                              able
                              > to carry it down the cellar steps... ;)
                              >
                              >
                              > Thanks,
                              > Charlie
                              >
                            • CLevinski
                              Robert, Ben, Wow! I tried a 3/8 inch end mill with the same .025 inch deep cut, making a full width cut rather than using only part of the width. The
                              Message 14 of 24 , May 12, 2013
                                Robert, Ben,

                                Wow! I tried a 3/8 inch end mill with the same .025 inch deep cut,
                                making a full width cut rather than using only part of the width. The
                                vibration was MUCH less, the cut was much smoother, and I could go much
                                faster, even at the original speed. Then I increased speed to about
                                1250 RPM, and it was even faster. I would estimate I'm going 4 times
                                faster than yesterday, including the fact that I am making fewer passes
                                to remove the material due to the larger cut (approx. 0.375 inchs per
                                pass instead of 5/8 divided by 3, or .208 inches per pass).

                                Thanks to you both for the invaluable advice!

                                Charlie


                                --- In GrizHFMinimill@yahoogroups.com, "CLevinski" wrote:
                                >
                                > Hi, Robert,
                                >
                                > That's some very useful information. I would actually cut more
                                material
                                > with a full with 3/8 inch end mill than a 1/3 width 5/8 inch end mill,
                                > so that would speed things up. Your observations about the vibration
                                > make sense, so I'm going to give it a try. But either way, I'm better
                                > off to cut out as much stock as I can with other methods first.
                                >
                                > Many thanks,
                                > Charlie
                                >
                                >
                                > --- In GrizHFMinimill@yahoogroups.com, "Robert Furmanak" wrote:
                                > >
                                > > Charlie
                                > >
                                > >
                                > >
                                > > My experience is that the Mini Mill is not nearly stiff enough to
                                use
                                > a 5/8
                                > > end mill. It does not matter that you are only using 1/3 of the
                                > diameter,
                                > > what matters is that you are putting a considerable side load on the
                                > machine
                                > > with every pass the cutting edge makes. I'm willing to bet you
                                would
                                > make
                                > > twice as much progress with a 3/8 end mill. Also, I have found that
                                > even
                                > > with the smaller end mill, there is far less vibration when using
                                the
                                > full
                                > > width of the end mill, rather than the side. Here is how I would
                                > handle
                                > > your problem. Use a 3/8 end mill, and make 3/8 wide cuts. I think
                                > you will
                                > > find that the machine is quietest when the end mill has a large
                                > contact area
                                > > with the material being cut. The reason is that there are always at
                                > least
                                > > two flutes in contact with the material, while your method of using
                                > 1/3 the
                                > > diameter likely has just one flute in contact, creating an
                                alternating
                                > cycle
                                > > of high loads going to near zero load, and back.
                                > >
                                > >
                                > >
                                > > As for climb milling, I think that has been given a bad rap. I read
                                a
                                > good
                                > > paper on the physics of it a while ago, and climb milling is
                                actually
                                > less
                                > > stressful to the cutting edge. The problem arises when the machine
                                is
                                > too
                                > > loose, and allows the end mill to pull itself deeper into the
                                > material. I
                                > > do all my finishing cuts as climbing cuts, and I have my machine set
                                > very
                                > > tight. When using the full width of the end mill as I suggested
                                > above, the
                                > > climbing forces are held in check by the resistance the other side
                                is
                                > > experiencing. However, with very small end mills, the mill will try
                                > to
                                > > climb sideways by bending, so one has to watch for that, at 1/8 inch
                                > > diameter and below.
                                > >
                                > >
                                > >
                                > > Robert
                                > >
                                > >
                                > >
                                > > From: GrizHFMinimill@yahoogroups.com
                                > [mailto:GrizHFMinimill@yahoogroups.com]
                                > > On Behalf Of CLevinski
                                > > Sent: Saturday, May 11, 2013 4:49 PM
                                > > To: GrizHFMinimill@yahoogroups.com
                                > > Subject: [GrizHFMinimill] How would YOU do this?
                                > >
                                > >
                                > >
                                > >
                                > >
                                > > Hi,
                                > >
                                > > While I've done a number of small projects on my lathe, my mini-mill
                                > is
                                > > definitely underutilized. So I started a little project today that
                                > involves
                                > > taking a 1.150 x 1.850 inch piece of aluminum I had lying around,
                                and
                                > sizing
                                > > it to make a widget. Only problem is that it was almost 1.500
                                inches
                                > thick,
                                > > and I need it to be 1.000 inches thick. So I thought, "Nah, I don't
                                > need to
                                > > use the band saw! I'll just mill that puppy down.". Almost 2 hours
                                > of
                                > > continuous milling later (while wearing hearing protection, because
                                I
                                > > haven't made a belt drive conversion), it is now down to 1.250
                                inches.
                                > I'm
                                > > face milling with a 5/8 inch end mill, only engaging about 1/3 of
                                the
                                > > diameter, never climb milling, and cutting in all four directions.
                                > > (Essentially cutting in a counter-clockwise rectangle.) I'm running
                                > the
                                > > mini-mill fairly slowly (maybe 600 RPM?, though I tried it nearer to
                                > 900 RPM
                                > > and didn't pick up any noticeable benefit except for greater
                                > swarf-throwing
                                > > range). I tried cuts from .020 to .030 inches and settled on .025
                                > inches as
                                > > maximum material removal without excess noise.
                                > >
                                > > I have a fly cutter set (though I've never used it) but fly cutters
                                > are
                                > > primarily for finishing cuts, I understand, so I don't think that's
                                > the
                                > > solution.
                                > >
                                > > So my question; how would YOU more experienced guys do this? Is
                                there
                                > a
                                > > technique I'm missing that would allow me to do this faster? Since
                                > this
                                > > isn't a finishing cut, could I use the full end mill width? That
                                > would
                                > > certainly speed up the process but I read that it's bad for the end
                                > mill
                                > > (specially a four-flute) since one side is conventional milling and
                                > the
                                > > other side is climb milling.
                                > >
                                > > And yes, if I can't find a better way, I'll probably go back to the
                                > band saw
                                > > and then make a couple of passes with the mill to finish the
                                surface.
                                > >
                                > > Times like this, I wish I had a Bridgeport. But I don't think I'd
                                be
                                > able
                                > > to carry it down the cellar steps... ;)
                                > >
                                > >
                                > > Thanks,
                                > > Charlie
                                > >
                                >
                              • michael kolchins
                                I would cut it with a hacksaw first about 1/16 from the line. Then mill the rest by side milling. I get better results side milling the face milling with an
                                Message 15 of 24 , May 12, 2013
                                  I would cut it with a hacksaw first about 1/16" from the line. Then mill the rest by side milling. I get better results side milling the face milling with an endmill.
                                  mike


                                  From: CLevinski <clevinski@...>
                                  To: GrizHFMinimill@yahoogroups.com
                                  Sent: Saturday, May 11, 2013 4:48 PM
                                  Subject: [GrizHFMinimill] How would YOU do this?

                                   
                                  Hi,

                                  While I've done a number of small projects on my lathe, my mini-mill is definitely underutilized.  So I started a little project today that involves taking a 1.150 x 1.850 inch piece of aluminum I had lying around, and sizing it to make a widget.  Only problem is that it was almost 1.500 inches thick, and I need it to be 1.000 inches thick.  So I thought, "Nah, I don't need to use the band saw!  I'll just mill that puppy down.".  Almost 2 hours of continuous milling later (while wearing hearing protection, because I haven't made a belt drive conversion), it is now down to 1.250 inches.  I'm face milling with a 5/8 inch end mill, only engaging about 1/3 of the diameter, never climb milling, and cutting in all four directions.  (Essentially cutting in a counter-clockwise rectangle.)  I'm running the mini-mill fairly slowly (maybe 600 RPM?, though I tried it nearer to 900 RPM and didn't pick up any noticeable benefit except for greater swarf-throwing range).  I tried cuts from .020 to .030 inches and settled on .025 inches as maximum material removal without excess noise.

                                  I have a fly cutter set (though I've never used it) but fly cutters are primarily for finishing cuts, I understand, so I don't think that's the solution.

                                  So my question; how would YOU more experienced guys do this?  Is there a technique I'm missing that would allow me to do this faster?  Since this isn't a finishing cut, could I use the full end mill width?  That would certainly speed up the process but I read that it's bad for the end mill (specially a four-flute) since one side is conventional milling and the other side is climb milling.

                                  And yes, if I can't find a better way, I'll probably go back to the band saw and then make a couple of passes with the mill to finish the surface.

                                  Times like this, I wish I had a Bridgeport.  But I don't think I'd be able to carry it down the cellar steps... ;)

                                  Thanks,
                                  Charlie



                                • CLevinski
                                  Hi, Mike, Thanks for the suggestion... I prefer side milling, too, but the surface is too deep for the side of the mill to reach down completely. Thanks,
                                  Message 16 of 24 , May 13, 2013
                                    Hi, Mike,

                                    Thanks for the suggestion... I prefer side milling, too, but the surface
                                    is too deep for the side of the mill to reach down completely.

                                    Thanks,
                                    Charlie


                                    --- In GrizHFMinimill@yahoogroups.com, michael kolchins wrote:
                                    >
                                    > I would cut it with a hacksaw first about 1/16" from the line. Then
                                    mill the rest by side milling. I get better results side milling the
                                    face milling with an endmill.
                                    > mike
                                    >
                                    >
                                    >
                                    > >________________________________
                                    > > From: CLevinski clevinski@...
                                    > >To: GrizHFMinimill@yahoogroups.com
                                    > >Sent: Saturday, May 11, 2013 4:48 PM
                                    > >Subject: [GrizHFMinimill] How would YOU do this?
                                    > >
                                    > >
                                    > >
                                    > >Â
                                    > >Hi,
                                    > >
                                    > >While I've done a number of small projects on my lathe, my mini-mill
                                    is definitely underutilized. So I started a little project today
                                    that involves taking a 1.150 x 1.850 inch piece of aluminum I had lying
                                    around, and sizing it to make a widget. Only problem is that it was
                                    almost 1.500 inches thick, and I need it to be 1.000 inches thick.Â
                                    So I thought, "Nah, I don't need to use the band saw! I'll just
                                    mill that puppy down.". Almost 2 hours of continuous milling later
                                    (while wearing hearing protection, because I haven't made a belt drive
                                    conversion), it is now down to 1.250 inches. I'm face milling with
                                    a 5/8 inch end mill, only engaging about 1/3 of the diameter, never
                                    climb milling, and cutting in all four directions. (Essentially
                                    cutting in a counter-clockwise rectangle.)Â I'm running the
                                    mini-mill fairly slowly (maybe 600 RPM?, though I tried it nearer to 900
                                    RPM and didn't pick up any noticeable benefit
                                    > except for greater swarf-throwing range). I tried cuts from .020
                                    to .030 inches and settled on .025 inches as maximum material removal
                                    without excess noise.
                                    > >
                                    > >I have a fly cutter set (though I've never used it) but fly cutters
                                    are primarily for finishing cuts, I understand, so I don't think that's
                                    the solution.
                                    > >
                                    > >So my question; how would YOU more experienced guys do this? Is
                                    there a technique I'm missing that would allow me to do this faster?Â
                                    Since this isn't a finishing cut, could I use the full end mill
                                    width? That would certainly speed up the process but I read that
                                    it's bad for the end mill (specially a four-flute) since one side is
                                    conventional milling and the other side is climb milling.
                                    > >
                                    > >And yes, if I can't find a better way, I'll probably go back to the
                                    band saw and then make a couple of passes with the mill to finish the
                                    surface.
                                    > >
                                    > >Times like this, I wish I had a Bridgeport. But I don't think
                                    I'd be able to carry it
                                    > down the cellar steps...
                                    > >
                                    > >Thanks,
                                    > >Charlie
                                    > >
                                    > >
                                    > >
                                    > >
                                    > >
                                    >
                                  • kaje7777
                                    I would have rough-cut the piece using a hack saw (even a large piece of aluminum cuts pretty quickly), and then finish milled to size. The cut-off piece might
                                    Message 17 of 24 , May 14, 2013
                                      I would have rough-cut the piece using a hack saw (even a large piece of aluminum cuts pretty quickly), and then finish milled to size. The cut-off piece might well be large enough to use in some other project, which is better that just turning it into swarf.

                                      --- In GrizHFMinimill@yahoogroups.com, "CLevinski" <clevinski@...> wrote:
                                      >
                                      > Hi,
                                      >
                                      > While I've done a number of small projects on my lathe, my mini-mill is
                                      > definitely underutilized. So I started a little project today that
                                      > involves taking a 1.150 x 1.850 inch piece of aluminum I had lying
                                      > around, and sizing it to make a widget. Only problem is that it was
                                      > almost 1.500 inches thick, and I need it to be 1.000 inches thick. So I
                                      > thought, "Nah, I don't need to use the band saw! I'll just mill that
                                      > puppy down.". Almost 2 hours of continuous milling later (while wearing
                                      > hearing protection, because I haven't made a belt drive conversion), it
                                      > is now down to 1.250 inches. I'm face milling with a 5/8 inch end mill,
                                      > only engaging about 1/3 of the diameter, never climb milling, and
                                      > cutting in all four directions. (Essentially cutting in a
                                      > counter-clockwise rectangle.) I'm running the mini-mill fairly slowly
                                      > (maybe 600 RPM?, though I tried it nearer to 900 RPM and didn't pick up
                                      > any noticeable benefit except for greater swarf-throwing range). I
                                      > tried cuts from .020 to .030 inches and settled on .025 inches as
                                      > maximum material removal without excess noise.
                                      >
                                      > I have a fly cutter set (though I've never used it) but fly cutters are
                                      > primarily for finishing cuts, I understand, so I don't think that's the
                                      > solution.
                                      >
                                      > So my question; how would YOU more experienced guys do this? Is there a
                                      > technique I'm missing that would allow me to do this faster? Since this
                                      > isn't a finishing cut, could I use the full end mill width? That would
                                      > certainly speed up the process but I read that it's bad for the end mill
                                      > (specially a four-flute) since one side is conventional milling and the
                                      > other side is climb milling.
                                      >
                                      > And yes, if I can't find a better way, I'll probably go back to the band
                                      > saw and then make a couple of passes with the mill to finish the
                                      > surface.
                                      >
                                      > Times like this, I wish I had a Bridgeport. But I don't think I'd be
                                      > able to carry it down the cellar steps... [;)]
                                      >
                                      > Thanks,
                                      > Charlie
                                      >
                                    • Ian Newman
                                      Hi,   Use a 3/8 end mill, and make 3/8 wide cuts. I think you will find that the machine is quietest when the end mill has a large contact area with
                                      Message 18 of 24 , May 15, 2013
                                        Hi,
                                         
                                        <SNIP>
                                        Use a 3/8 end mill, and make 3/8 wide cuts. I think you will find that the machine is quietest when the end mill has a large contact area with the material being cut. The reason is that there are always at least two flutes in contact with the material, while your method of using 1/3 the diameter likely has just one flute in contact, creating an alternating cycle of high loads going to near zero load, and back.
                                        </SNIP>
                                         
                                        I would take a different view to that expressed above - depending on the type of cutter you are using.
                                         
                                        Before I start a word about my terminology - I'm in the UK and in this part of the world an end mill is never able to centre cut, what is called a centre cutting end mill in the USA, we call a slot drill. Slot drills usually have two (sometimes three) flutes, end mills have four or more.

                                        For slot cutting, or cutting the full width of the cutter, you should not use an end mill - the four flutes make it almost impossible to cut a smooth side to the slot.

                                        To get a idea of the problem, imagine a four flute cutter cutting a slot (so it is cutting the full width of the cutter). Picture the plan view of the job, the cutter rotating clockwise and call the direction of the pass over the material the "front".

                                        As one of the cutter teeth cuts away the front of the slot, it will tend to bend the cutter to the left (looking at the plan view) and push the left hand cutter tooth into the side of the slot. This causes a very rough, lumpy and poor quality side to the slot - this is why you should not cut a slot with a end mill (or if you do, use a cutter smaller than the width of the slot that you wish to cut and cut each side of the slot separately). The two flute slot drill does not suffer from this problem as when the front of the slot is being cut and the cutter flexes, there is no other tooth in contact with the slot sides.

                                        The usual recommendation is to limit the width of the cut for an end mill to less than 1/4 of the cutter diameter of the cutter, thus minimising the sideways flexing of the cutting tool and the associated problems.

                                        Attempts to cut both sides of a slot at the same time with an end mill often results in the corner of the tooth chipping off the cutter (due to the flexing/digging in problem) - this can be avoided by stoning a small bevel on the tip of each tooth. It need not be much, just 20 to 30 thou or so.
                                        All the best,
                                        Ian.
                                         
                                         
                                         
                                        From: Robert Furmanak <rfurmanak@...>
                                        To: GrizHFMinimill@yahoogroups.com
                                        Sent: Sunday, 12 May 2013, 3:35
                                        Subject: RE: [GrizHFMinimill] How would YOU do this?
                                         
                                        Charlie
                                         
                                        My experience is that the Mini Mill is not nearly stiff enough to use a 5/8 end mill.  It does not matter that you are only using 1/3 of the diameter, what matters is that you are putting a considerable side load on the machine with every pass the cutting edge makes.  I’m willing to bet you would make twice as much progress with a 3/8 end mill.  Also, I have found that even with the smaller end mill, there is far less vibration when using the full width of the end mill, rather than the side.  Here is how I would handle your problem.  Use a 3/8 end mill, and make 3/8 wide cuts.  I think you will find that the machine is quietest when the end mill has a large contact area with the material being cut.  The reason is that there are always at least two flutes in contact with the material, while your method of using 1/3 the diameter likely has just one flute in contact, creating an alternating cycle of high loads going to near zero load, and back.
                                         
                                        As for climb milling, I think that has been given a bad rap.  I read a good paper on the physics of it a while ago, and climb milling is actually less stressful to the cutting edge.  The problem arises when the machine is too loose, and allows the end mill to pull itself deeper into the material.  I do all my finishing cuts as climbing cuts, and I have my machine set very tight.   When using the full width of the end mill as I suggested above, the climbing forces are held in check by the resistance the other side is experiencing.  However, with very small end mills, the mill will try to climb sideways by bending, so one has to watch for that, at 1/8 inch diameter and below.  
                                         
                                        Robert
                                         
                                        From: GrizHFMinimill@yahoogroups.com [mailto:GrizHFMinimill@yahoogroups.com] On Behalf Of CLevinski
                                        Sent: Saturday, May 11, 2013 4:49 PM
                                        To: GrizHFMinimill@yahoogroups.com
                                        Subject: [GrizHFMinimill] How would YOU do this?
                                         
                                         
                                        Hi,

                                        While I've done a number of small projects on my lathe, my mini-mill is definitely underutilized.  So I started a little project today that involves taking a 1.150 x 1.850 inch piece of aluminum I had lying around, and sizing it to make a widget.  Only problem is that it was almost 1.500 inches thick, and I need it to be 1.000 inches thick.  So I thought, "Nah, I don't need to use the band saw!  I'll just mill that puppy down.".  Almost 2 hours of continuous milling later (while wearing hearing protection, because I haven't made a belt drive conversion), it is now down to 1.250 inches.  I'm face milling with a 5/8 inch end mill, only engaging about 1/3 of the diameter, never climb milling, and cutting in all four directions.  (Essentially cutting in a counter-clockwise rectangle.)  I'm running the mini-mill fairly slowly (maybe 600 RPM?, though I tried it nearer to 900 RPM and didn't pick up any noticeable benefit except for greater swarf-throwing range).  I tried cuts from .020 to .030 inches and settled on .025 inches as maximum material removal without excess noise.

                                        I have a fly cutter set (though I've never used it) but fly cutters are primarily for finishing cuts, I understand, so I don't think that's the solution.

                                        So my question; how would YOU more experienced guys do this?  Is there a technique I'm missing that would allow me to do this faster?  Since this isn't a finishing cut, could I use the full end mill width?  That would certainly speed up the process but I read that it's bad for the end mill (specially a four-flute) since one side is conventional milling and the other side is climb milling.

                                        And yes, if I can't find a better way, I'll probably go back to the band saw and then make a couple of passes with the mill to finish the surface.

                                        Times like this, I wish I had a Bridgeport.  But I don't think I'd be able to carry it down the cellar steps... ;)

                                        Thanks,
                                        Charlie
                                      • CLevinski
                                        Hi, Ian, Thanks for the detailed explanation, which makes perfect sense. I think the reason this is working for me is that I am not cutting a slot, but rather
                                        Message 19 of 24 , May 16, 2013
                                          Hi, Ian,

                                          Thanks for the detailed explanation, which makes perfect sense. I think
                                          the reason this is working for me is that I am not cutting a slot, but
                                          rather facing the entire surface. The width of my cut is slightly less
                                          that the cutter, and I'm starting on the outer periphery and making
                                          counterclockwise cuts around the outside. This way, there is no
                                          material opposite most of the side being cut. (There is a small portion
                                          at the front of the cut.) Since I'm reducing the height of the surface,
                                          the finish of the sides doesn't matter to me, since they are removed
                                          anyway, leaving me with a flat surface. I would actually have preferred
                                          to use the side of the end mill to make the cut, but it's not quite long
                                          enough.

                                          Thanks,
                                          Charlie

                                          --- In GrizHFMinimill@yahoogroups.com, Ian Newman wrote:
                                          >
                                          > Hi,
                                          > Â
                                          >
                                          > Use a 3/8 end mill, and make 3/8 wide cuts. I think you will find
                                          that the machine is quietest when the end mill has a large contact area
                                          with the material being cut. The reason is that there are always at
                                          least two flutes in contact with the material, while your method of
                                          using 1/3 the diameter likely has just one flute in contact, creating an
                                          alternating cycle of high loads going to near zero load, and back.
                                          >
                                          > Â
                                          > I would take a different view to that expressed above - depending on
                                          the type of cutter you are using.
                                          > Â
                                          > Before I start a word about my terminology - I'm in the UK and in this
                                          part of the world an end mill is never able to centre cut, what is
                                          called a centre cutting end mill in the USA, we call a slot drill.
                                          Slot drills usually have two (sometimes three) flutes, end mills have
                                          four or more.
                                          >
                                          > For slot cutting, or cutting the full width of the cutter, you
                                          should not use an end mill - the four flutes make it almost impossible
                                          to cut a smooth side to the slot.
                                          >
                                          > To get a idea of the problem, imagine a four flute cutter cutting a
                                          slot (so it is cutting the full width of the cutter). Picture the plan
                                          view of the job, the cutter rotating clockwise and call the direction
                                          of the pass over the material the "front".
                                          >
                                          > As one of the cutter teeth cuts away the front of the slot, it will
                                          tend to bend the cutter to the left (looking at the plan view) and push
                                          the left hand cutter tooth into the side of the slot. This causes a
                                          very rough, lumpy and poor quality side to the slot - this is why you
                                          should not cut a slot with a end mill (or if you do, use a
                                          cutter smaller than the width of the slot that you wish to cut and cut
                                          each side of the slot separately). The two flute slot drill does not
                                          suffer from this problem as when the front of the slot is being cut and
                                          the cutter flexes, there is no other tooth in contact with the slot
                                          sides.
                                          >
                                          > The usual recommendation is to limit the width of the cut for an end
                                          mill to less than 1/4 of the cutter diameter of the cutter, thus
                                          minimising the sideways flexing of the cutting tool and the associated
                                          problems.
                                          >
                                          > Attempts to cut both sides of a slot at the same time with an end mill
                                          often results in the corner of the tooth chipping off the cutter (due to
                                          the flexing/digging in problem) - this can be avoided by stoning a small
                                          bevel on the tip of each tooth. It need not be much, just 20 to 30 thou
                                          or so.
                                          >
                                          > All the best,
                                          > Ian.
                                          >
                                          > Â
                                          > Â
                                          > Â
                                          >
                                          > ________________________________
                                          > From: Robert Furmanak rfurmanak@...
                                          > To: GrizHFMinimill@yahoogroups.com
                                          > Sent: Sunday, 12 May 2013, 3:35
                                          > Subject: RE: [GrizHFMinimill] How would YOU do this?
                                          >
                                          >
                                          > Â
                                          >
                                          > Charlie
                                          > Â
                                          > My experience is that the Mini Mill is not nearly stiff enough to use
                                          a 5/8 end mill. It does not matter that you are only using 1/3 of
                                          the diameter, what matters is that you are putting a considerable side
                                          load on the machine with every pass the cutting edge makes.Â
                                          I’m willing to bet you would make twice as much progress with a
                                          3/8 end mill. Also, I have found that even with the smaller end
                                          mill, there is far less vibration when using the full width of the end
                                          mill, rather than the side. Here is how I would handle your
                                          problem. Use a 3/8 end mill, and make 3/8 wide cuts. I think
                                          you will find that the machine is quietest when the end mill has a large
                                          contact area with the material being cut. The reason is that there
                                          are always at least two flutes in contact with the material, while your
                                          method of using 1/3 the diameter likely has just one flute in contact,
                                          creating an alternating cycle of high loads going to near zero load, and
                                          back.
                                          > Â
                                          > As for climb milling, I think that has been given a bad rap. I
                                          read a good paper on the physics of it a while ago, and climb milling is
                                          actually less stressful to the cutting edge. The problem arises
                                          when the machine is too loose, and allows the end mill to pull itself
                                          deeper into the material. I do all my finishing cuts as climbing
                                          cuts, and I have my machine set very tight. Â Â When using the
                                          full width of the end mill as I suggested above, the climbing forces are
                                          held in check by the resistance the other side is experiencing.Â
                                          However, with very small end mills, the mill will try to climb sideways
                                          by bending, so one has to watch for that, at 1/8 inch diameter and
                                          below. Â
                                          > Â
                                          > Robert
                                          > Â
                                          > From:GrizHFMinimill@yahoogroups.com
                                          [mailto:GrizHFMinimill@yahoogroups.com] On Behalf Of CLevinski
                                          > Sent: Saturday, May 11, 2013 4:49 PM
                                          > To: GrizHFMinimill@yahoogroups.com
                                          > Subject: [GrizHFMinimill] How would YOU do this?
                                          > Â
                                          > Â
                                          > Hi,
                                          >
                                          > While I've done a number of small projects on my lathe, my mini-mill
                                          is definitely underutilized. So I started a little project today
                                          that involves taking a 1.150 x 1.850 inch piece of aluminum I had lying
                                          around, and sizing it to make a widget. Only problem is that it was
                                          almost 1.500 inches thick, and I need it to be 1.000 inches thick.Â
                                          So I thought, "Nah, I don't need to use the band saw! I'll just
                                          mill that puppy down.". Almost 2 hours of continuous milling later
                                          (while wearing hearing protection, because I haven't made a belt drive
                                          conversion), it is now down to 1.250 inches. I'm face milling with
                                          a 5/8 inch end mill, only engaging about 1/3 of the diameter, never
                                          climb milling, and cutting in all four directions. (Essentially
                                          cutting in a counter-clockwise rectangle.)Â I'm running the
                                          mini-mill fairly slowly (maybe 600 RPM?, though I tried it nearer to 900
                                          RPM and didn't pick up any noticeable benefit except for greater
                                          > swarf-throwing range). I tried cuts from .020 to .030 inches and
                                          settled on .025 inches as maximum material removal without excess noise.
                                          >
                                          > I have a fly cutter set (though I've never used it) but fly cutters
                                          are primarily for finishing cuts, I understand, so I don't think that's
                                          the solution.
                                          >
                                          > So my question; how would YOU more experienced guys do this? Is
                                          there a technique I'm missing that would allow me to do this faster?Â
                                          Since this isn't a finishing cut, could I use the full end mill
                                          width? That would certainly speed up the process but I read that
                                          it's bad for the end mill (specially a four-flute) since one side is
                                          conventional milling and the other side is climb milling.
                                          >
                                          > And yes, if I can't find a better way, I'll probably go back to the
                                          band saw and then make a couple of passes with the mill to finish the
                                          surface.
                                          >
                                          > Times like this, I wish I had a Bridgeport. But I don't think I'd
                                          be able to carry it down the cellar steps...
                                          >
                                          > Thanks,
                                          > Charlie
                                          >
                                        • Robert Furmanak
                                          Ian, Your advice is good, and I do not disagree with a word of it. However, the problem needing to be solved was rapid removal of material, not quality of
                                          Message 20 of 24 , May 17, 2013

                                            Ian,

                                             

                                              Your advice is good, and I do not disagree with a word of it.  However, the problem needing  to be solved was rapid removal of material, not quality of the cut.

                                            Everything you said about the tendency of an end mill to flex in a slot is correct, however I have found that to be the lesser of two evils,  with the greater evil the considerable flexibility of the Mini Mill. 

                                             I ran a test to see how much material I could remove rapidly, in response to the original question:

                                             

                                            “So I started a little project today that involves taking a 1.150 x 1.850 inch piece of aluminum I had lying around, and sizing it to make a widget.  Only problem is that it was almost 1.500 inches thick, and I need it to be 1.000 inches thick.  So I thought, "Nah, I don't need to use the band saw!  I'll just mill that puppy down.".  Almost 2 hours of continuous milling later (while wearing hearing protection, because I haven't made a belt drive conversion), it is now down to 1.250 inches.”

                                             

                                            I used a 1/2 inch 4 flute carbide end mill, and removed 1mm of aluminum at a speed of 240 mm/min with a minimum of vibration. I used the full with of the end mill.  1.25 mm deep cuts might have been OK,  but 2 mm was definitely too much.

                                            It took me 4 minutes to remove 5.5 mm from a 64 x 19 mm block.  At that rate, I could have milled the  29.2 x 47mm block mentioned above down 12.7mm in about 12 minutes, instead of 4 hours.   

                                             

                                            The Mini Mill is so flexible that end mill flexibility is only a factor below ¼ inch.  I have now modified my Mini Mill with a solid column and large table.  Now it is maybe 10 times better than my original mill.  

                                            The other day,  I was surfacing a piece of aluminum with a ¾ inch carbide facing tool.  The aluminum had an imbedded steel screw flush with the surface. The screw was 2 mm  in diameter.  I was only taking off maybe .02mm at a time, yet the screw deflected the cutter enough to cause it to dig deeper on the opposite side.  Not much, just enough to ruin the appearance of the surface.  No matter how small a cut I tried, it happened every time.  Then I put light pressure on the head of  the machine while the cutter was turning.  Even though I h ad the Z axis locked tight, and I run my gibs tight, a few ounces of pressure was all it took to tilt the head back enough to raise the fly cutter away from the surface it was cutting.  That is how flexible these machines are.

                                            I realize that at times I break some long held conventions when it comes to milling, but what I am doing is adapting my techniques  to accommodate the limitations of the mini mill.

                                             

                                            Regards,

                                             

                                            Robert

                                             

                                            From: GrizHFMinimill@yahoogroups.com [mailto:GrizHFMinimill@yahoogroups.com] On Behalf Of Ian Newman
                                            Sent: Wednesday, May 15, 2013 8:17 AM
                                            To: GrizHFMinimill@yahoogroups.com
                                            Subject: Re: [GrizHFMinimill] How would YOU do this?

                                             

                                             

                                            Hi,

                                             

                                            <SNIP>

                                            Use a 3/8 end mill, and make 3/8 wide cuts. I think you will find that the machine is quietest when the end mill has a large contact area with the material being cut. The reason is that there are always at least two flutes in contact with the material, while your method of using 1/3 the diameter likely has just one flute in contact, creating an alternating cycle of high loads going to near zero load, and back.

                                            </SNIP>

                                             

                                            I would take a different view to that expressed above - depending on the type of cutter you are using.

                                             

                                            Before I start a word about my terminology - I'm in the UK and in this part of the world an end mill is never able to centre cut, what is called a centre cutting end mill in the USA, we call a slot drill. Slot drills usually have two (sometimes three) flutes, end mills have four or more.

                                            For slot cutting, or cutting the full width of the cutter, you should not use an end mill - the four flutes make it almost impossible to cut a smooth side to the slot.

                                            To get a idea of the problem, imagine a four flute cutter cutting a slot (so it is cutting the full width of the cutter). Picture the plan view of the job, the cutter rotating clockwise and call the direction of the pass over the material the "front".

                                            As one of the cutter teeth cuts away the front of the slot, it will tend to bend the cutter to the left (looking at the plan view) and push the left hand cutter tooth into the side of the slot. This causes a very rough, lumpy and poor quality side to the slot - this is why you should not cut a slot with a end mill (or if you do, use a cutter smaller than the width of the slot that you wish to cut and cut each side of the slot separately). The two flute slot drill does not suffer from this problem as when the front of the slot is being cut and the cutter flexes, there is no other tooth in contact with the slot sides.

                                            The usual recommendation is to limit the width of the cut for an end mill to less than 1/4 of the cutter diameter of the cutter, thus minimising the sideways flexing of the cutting tool and the associated problems.

                                            Attempts to cut both sides of a slot at the same time with an end mill often results in the corner of the tooth chipping off the cutter (due to the flexing/digging in problem) - this can be avoided by stoning a small bevel on the tip of each tooth. It need not be much, just 20 to 30 thou or so.

                                            All the best,
                                            Ian.

                                             

                                             

                                             

                                            From: Robert Furmanak <rfurmanak@...>
                                            To: GrizHFMinimill@yahoogroups.com
                                            Sent: Sunday, 12 May 2013, 3:35
                                            Subject: RE: [GrizHFMinimill] How would YOU do this?

                                             

                                            Charlie

                                             

                                            My experience is that the Mini Mill is not nearly stiff enough to use a 5/8 end mill.  It does not matter that you are only using 1/3 of the diameter, what matters is that you are putting a considerable side load on the machine with every pass the cutting edge makes.  I’m willing to bet you would make twice as much progress with a 3/8 end mill.  Also, I have found that even with the smaller end mill, there is far less vibration when using the full width of the end mill, rather than the side.  Here is how I would handle your problem.  Use a 3/8 end mill, and make 3/8 wide cuts.  I think you will find that the machine is quietest when the end mill has a large contact area with the material being cut.  The reason is that there are always at least two flutes in contact with the material, while your method of using 1/3 the diameter likely has just one flute in contact, creating an alternating cycle of high loads going to near zero load, and back.

                                             

                                            As for climb milling, I think that has been given a bad rap.  I read a good paper on the physics of it a while ago, and climb milling is actually less stressful to the cutting edge.  The problem arises when the machine is too loose, and allows the end mill to pull itself deeper into the material.  I do all my finishing cuts as climbing cuts, and I have my machine set very tight.   When using the full width of the end mill as I suggested above, the climbing forces are held in check by the resistance the other side is experiencing.  However, with very small end mills, the mill will try to climb sideways by bending, so one has to watch for that, at 1/8 inch diameter and below.  

                                             

                                            Robert

                                             

                                            From: GrizHFMinimill@yahoogroups.com [mailto:GrizHFMinimill@yahoogroups.com] On Behalf Of CLevinski
                                            Sent: Saturday, May 11, 2013 4:49 PM
                                            To: GrizHFMinimill@yahoogroups.com
                                            Subject: [GrizHFMinimill] How would YOU do this?

                                             

                                             

                                            Hi,

                                            While I've done a number of small projects on my lathe, my mini-mill is definitely underutilized.  So I started a little project today that involves taking a 1.150 x 1.850 inch piece of aluminum I had lying around, and sizing it to make a widget.  Only problem is that it was almost 1.500 inches thick, and I need it to be 1.000 inches thick.  So I thought, "Nah, I don't need to use the band saw!  I'll just mill that puppy down.".  Almost 2 hours of continuous milling later (while wearing hearing protection, because I haven't made a belt drive conversion), it is now down to 1.250 inches.  I'm face milling with a 5/8 inch end mill, only engaging about 1/3 of the diameter, never climb milling, and cutting in all four directions.  (Essentially cutting in a counter-clockwise rectangle.)  I'm running the mini-mill fairly slowly (maybe 600 RPM?, though I tried it nearer to 900 RPM and didn't pick up any noticeable benefit except for greater swarf-throwing range).  I tried cuts from .020 to .030 inches and settled on .025 inches as maximum material removal without excess noise.

                                            I have a fly cutter set (though I've never used it) but fly cutters are primarily for finishing cuts, I understand, so I don't think that's the solution.

                                            So my question; how would YOU more experienced guys do this?  Is there a technique I'm missing that would allow me to do this faster?  Since this isn't a finishing cut, could I use the full end mill width?  That would certainly speed up the process but I read that it's bad for the end mill (specially a four-flute) since one side is conventional milling and the other side is climb milling.

                                            And yes, if I can't find a better way, I'll probably go back to the band saw and then make a couple of passes with the mill to finish the surface.

                                            Times like this, I wish I had a Bridgeport.  But I don't think I'd be able to carry it down the cellar steps... ;)

                                            Thanks,
                                            Charlie

                                          • gerry waclawiak
                                            I can only think that Robert s mill was a particularly bad example and poorly assembled and adjusted to boot. I have had my mill for several years and other
                                            Message 21 of 24 , May 17, 2013
                                              I can only think that Robert's mill was a particularly bad example and poorly assembled and adjusted to boot.

                                              I have had my mill for several years and other than the commonly discussed tweaks and adjustments is fundamentally stock.

                                              I made a belt drive conversion primarily for the noise reduction (bedroom workshop) and to give a degree of protection against breakage due to the increased use of fly cutters to surface stock relatively quickly and cheaply.

                                              I do not find the flex to be an particular issue with appropriate management and technique and due regard to the size and power of the machine

                                              Gerry W

                                              Leeds UK




                                              To: GrizHFMinimill@yahoogroups.com
                                              From: rfurmanak@...
                                              Date: Fri, 17 May 2013 13:07:00 -0400
                                              Subject: RE: [GrizHFMinimill] How would YOU do this?

                                               

                                              Ian,

                                               

                                                Your advice is good, and I do not disagree with a word of it.  However, the problem needing  to be solved was rapid removal of material, not quality of the cut.

                                              Everything you said about the tendency of an end mill to flex in a slot is correct, however I have found that to be the lesser of two evils,  with the greater evil the considerable flexibility of the Mini Mill. 

                                               I ran a test to see how much material I could remove rapidly, in response to the original question:

                                               

                                              “So I started a little project today that involves taking a 1.150 x 1.850 inch piece of aluminum I had lying around, and sizing it to make a widget.  Only problem is that it was almost 1.500 inches thick, and I need it to be 1.000 inches thick.  So I thought, "Nah, I don't need to use the band saw!  I'll just mill that puppy down.".  Almost 2 hours of continuous milling later (while wearing hearing protection, because I haven't made a belt drive conversion), it is now down to 1.250 inches.”

                                               

                                              I used a 1/2 inch 4 flute carbide end mill, and removed 1mm of aluminum at a speed of 240 mm/min with a minimum of vibration. I used the full with of the end mill.  1.25 mm deep cuts might have been OK,  but 2 mm was definitely too much.

                                              It took me 4 minutes to remove 5.5 mm from a 64 x 19 mm block.  At that rate, I could have milled the  29.2 x 47mm block mentioned above down 12.7mm in about 12 minutes, instead of 4 hours.   

                                               

                                              The Mini Mill is so flexible that end mill flexibility is only a factor below ¼ inch.  I have now modified my Mini Mill with a solid column and large table.  Now it is maybe 10 times better than my original mill.  

                                              The other day,  I was surfacing a piece of aluminum with a ¾ inch carbide facing tool.  The aluminum had an imbedded steel screw flush with the surface. The screw was 2 mm  in diameter.  I was only taking off maybe .02mm at a time, yet the screw deflected the cutter enough to cause it to dig deeper on the opposite side.  Not much, just enough to ruin the appearance of the surface.  No matter how small a cut I tried, it happened every time.  Then I put light pressure on the head of  the machine while the cutter was turning.  Even though I h ad the Z axis locked tight, and I run my gibs tight, a few ounces of pressure was all it took to tilt the head back enough to raise the fly cutter away from the surface it was cutting.  That is how flexible these machines are.

                                              I realize that at times I break some long held conventions when it comes to milling, but what I am doing is adapting my techniques  to accommodate the limitations of the mini mill.

                                               

                                              Regards,

                                               

                                              Robert

                                               

                                              From: GrizHFMinimill@yahoogroups.com [mailto:GrizHFMinimill@yahoogroups.com] On Behalf Of Ian Newman
                                              Sent: Wednesday, May 15, 2013 8:17 AM
                                              To: GrizHFMinimill@yahoogroups.com
                                              Subject: Re: [GrizHFMinimill] How would YOU do this?

                                               

                                               

                                              Hi,

                                               

                                              <SNIP>

                                              Use a 3/8 end mill, and make 3/8 wide cuts. I think you will find that the machine is quietest when the end mill has a large contact area with the material being cut. The reason is that there are always at least two flutes in contact with the material, while your method of using 1/3 the diameter likely has just one flute in contact, creating an alternating cycle of high loads going to near zero load, and back.

                                              </SNIP>

                                               

                                              I would take a different view to that expressed above - depending on the type of cutter you are using.

                                               

                                              Before I start a word about my terminology - I'm in the UK and in this part of the world an end mill is never able to centre cut, what is called a centre cutting end mill in the USA, we call a slot drill. Slot drills usually have two (sometimes three) flutes, end mills have four or more.

                                              For slot cutting, or cutting the full width of the cutter, you should not use an end mill - the four flutes make it almost impossible to cut a smooth side to the slot.

                                              To get a idea of the problem, imagine a four flute cutter cutting a slot (so it is cutting the full width of the cutter). Picture the plan view of the job, the cutter rotating clockwise and call the direction of the pass over the material the "front".

                                              As one of the cutter teeth cuts away the front of the slot, it will tend to bend the cutter to the left (looking at the plan view) and push the left hand cutter tooth into the side of the slot. This causes a very rough, lumpy and poor quality side to the slot - this is why you should not cut a slot with a end mill (or if you do, use a cutter smaller than the width of the slot that you wish to cut and cut each side of the slot separately). The two flute slot drill does not suffer from this problem as when the front of the slot is being cut and the cutter flexes, there is no other tooth in contact with the slot sides.

                                              The usual recommendation is to limit the width of the cut for an end mill to less than 1/4 of the cutter diameter of the cutter, thus minimising the sideways flexing of the cutting tool and the associated problems.

                                              Attempts to cut both sides of a slot at the same time with an end mill often results in the corner of the tooth chipping off the cutter (due to the flexing/digging in problem) - this can be avoided by stoning a small bevel on the tip of each tooth. It need not be much, just 20 to 30 thou or so.

                                              All the best,
                                              Ian.

                                               

                                               

                                               

                                              From: Robert Furmanak <rfurmanak@...>
                                              To: GrizHFMinimill@yahoogroups.com
                                              Sent: Sunday, 12 May 2013, 3:35
                                              Subject: RE: [GrizHFMinimill] How would YOU do this?

                                               

                                              Charlie

                                               

                                              My experience is that the Mini Mill is not nearly stiff enough to use a 5/8 end mill.  It does not matter that you are only using 1/3 of the diameter, what matters is that you are putting a considerable side load on the machine with every pass the cutting edge makes.  I’m willing to bet you would make twice as much progress with a 3/8 end mill.  Also, I have found that even with the smaller end mill, there is far less vibration when using the full width of the end mill, rather than the side.  Here is how I would handle your problem.  Use a 3/8 end mill, and make 3/8 wide cuts.  I think you will find that the machine is quietest when the end mill has a large contact area with the material being cut.  The reason is that there are always at least two flutes in contact with the material, while your method of using 1/3 the diameter likely has just one flute in contact, creating an alternating cycle of high loads going to near zero load, and back.

                                               

                                              As for climb milling, I think that has been given a bad rap.  I read a good paper on the physics of it a while ago, and climb milling is actually less stressful to the cutting edge.  The problem arises when the machine is too loose, and allows the end mill to pull itself deeper into the material.  I do all my finishing cuts as climbing cuts, and I have my machine set very tight.   When using the full width of the end mill as I suggested above, the climbing forces are held in check by the resistance the other side is experiencing.  However, with very small end mills, the mill will try to climb sideways by bending, so one has to watch for that, at 1/8 inch diameter and below.  

                                               

                                              Robert

                                               

                                              From: GrizHFMinimill@yahoogroups.com [mailto:GrizHFMinimill@yahoogroups.com] On Behalf Of CLevinski
                                              Sent: Saturday, May 11, 2013 4:49 PM
                                              To: GrizHFMinimill@yahoogroups.com
                                              Subject: [GrizHFMinimill] How would YOU do this?

                                               

                                               

                                              Hi,

                                              While I've done a number of small projects on my lathe, my mini-mill is definitely underutilized.  So I started a little project today that involves taking a 1.150 x 1.850 inch piece of aluminum I had lying around, and sizing it to make a widget.  Only problem is that it was almost 1.500 inches thick, and I need it to be 1.000 inches thick.  So I thought, "Nah, I don't need to use the band saw!  I'll just mill that puppy down.".  Almost 2 hours of continuous milling later (while wearing hearing protection, because I haven't made a belt drive conversion), it is now down to 1.250 inches.  I'm face milling with a 5/8 inch end mill, only engaging about 1/3 of the diameter, never climb milling, and cutting in all four directions.  (Essentially cutting in a counter-clockwise rectangle.)  I'm running the mini-mill fairly slowly (maybe 600 RPM?, though I tried it nearer to 900 RPM and didn't pick up any noticeable benefit except for greater swarf-throwing range).  I tried cuts from .020 to .030 inches and settled on .025 inches as maximum material removal without excess noise.

                                              I have a fly cutter set (though I've never used it) but fly cutters are primarily for finishing cuts, I understand, so I don't think that's the solution.

                                              So my question; how would YOU more experienced guys do this?  Is there a technique I'm missing that would allow me to do this faster?  Since this isn't a finishing cut, could I use the full end mill width?  That would certainly speed up the process but I read that it's bad for the end mill (specially a four-flute) since one side is conventional milling and the other side is climb milling.

                                              And yes, if I can't find a better way, I'll probably go back to the band saw and then make a couple of passes with the mill to finish the surface.

                                              Times like this, I wish I had a Bridgeport.  But I don't think I'd be able to carry it down the cellar steps... ;)

                                              Thanks,
                                              Charlie


                                            • Robert Furmanak
                                              Gerry, I am assuming that you have a Real Bull like most Europeans, and not a Sieg like most Americans. While I have not had the opportunity to do a side by
                                              Message 22 of 24 , May 19, 2013

                                                Gerry,

                                                 

                                                    I am assuming that you have a Real Bull like most Europeans, and not a Sieg like most Americans.  While I have not had the opportunity to do a side by side comparison, from what I have seen, the Real Bulls are somewhat better in most areas.  The original Sieg models with the small table and still sold by Harbor Freight, were especially bad.  The Y axis gib had only two setscrews.  That meant that under some operating conditions, the stresses transmitted through the carriage to the base were carried by only two 6mm screws.  It was nearly impossible to work a piece which was over 6 inches above the table, say for example when I had my rotary table and 3 inch chuck mounted on the mill.  Now the lever arm working against those two screws was relatively large, and it was impossible to keep the table from flexing.  The improved Sieg mill sold by Little Machine Shop has a much larger carriage and 4 setscrews. That fixed the table flex problem, and made using the rotary table much easier.

                                                   The original Sieg column is thin.  I remember reading the story one person who lightly compressed the bottom of a Sieg column with a C clamp while measuring the compression with a caliper.  It easily compressed a few thousandths of an inch in the area where the pivot bolt goes through.  That is flexible, and any flexibility at the base is magnified by the distance the head is up the column from the base.  It is this flexibility that has prompted many users here to try things like filling the column with epoxy.

                                                   Finally, we now have a Sieg mill comparable to yours in the LMS Solid Column Hi Torque mini mill.  So, in the future, please consider these differences before making generalized statements which imply that I do not know how to operate or adjust my mill.

                                                 

                                                Robert

                                                 

                                                From: GrizHFMinimill@yahoogroups.com [mailto:GrizHFMinimill@yahoogroups.com] On Behalf Of gerry waclawiak
                                                Sent: Friday, May 17, 2013 1:39 PM
                                                To: GrizHFMinimill@yahoogroups.com
                                                Subject: RE: [GrizHFMinimill] How would YOU do this?

                                                 

                                                 

                                                I can only think that Robert's mill was a particularly bad example and poorly assembled and adjusted to boot.

                                                I have had my mill for several years and other than the commonly discussed tweaks and adjustments is fundamentally stock.

                                                I made a belt drive conversion primarily for the noise reduction (bedroom workshop) and to give a degree of protection against breakage due to the increased use of fly cutters to surface stock relatively quickly and cheaply.

                                                I do not find the flex to be an particular issue with appropriate management and technique and due regard to the size and power of the machine

                                                Gerry W

                                                Leeds UK


                                                To: GrizHFMinimill@yahoogroups.com
                                                From: rfurmanak@...
                                                Date: Fri, 17 May 2013 13:07:00 -0400
                                                Subject: RE: [GrizHFMinimill] How would YOU do this?

                                                 

                                                 

                                                Ian,

                                                 

                                                  Your advice is good, and I do not disagree with a word of it.  However, the problem needing  to be solved was rapid removal of material, not quality of the cut.

                                                Everything you said about the tendency of an end mill to flex in a slot is correct, however I have found that to be the lesser of two evils,  with the greater evil the considerable flexibility of the Mini Mill. 

                                                 I ran a test to see how much material I could remove rapidly, in response to the original question:

                                                 

                                                “So I started a little project today that involves taking a 1.150 x 1.850 inch piece of aluminum I had lying around, and sizing it to make a widget.  Only problem is that it was almost 1.500 inches thick, and I need it to be 1.000 inches thick.  So I thought, "Nah, I don't need to use the band saw!  I'll just mill that puppy down.".  Almost 2 hours of continuous milling later (while wearing hearing protection, because I haven't made a belt drive conversion), it is now down to 1.250 inches.”

                                                 

                                                I used a 1/2 inch 4 flute carbide end mill, and removed 1mm of aluminum at a speed of 240 mm/min with a minimum of vibration. I used the full with of the end mill.  1.25 mm deep cuts might have been OK,  but 2 mm was definitely too much.

                                                It took me 4 minutes to remove 5.5 mm from a 64 x 19 mm block.  At that rate, I could have milled the  29.2 x 47mm block mentioned above down 12.7mm in about 12 minutes, instead of 4 hours.   

                                                 

                                                The Mini Mill is so flexible that end mill flexibility is only a factor below ¼ inch.  I have now modified my Mini Mill with a solid column and large table.  Now it is maybe 10 times better than my original mill.  

                                                The other day,  I was surfacing a piece of aluminum with a ¾ inch carbide facing tool.  The aluminum had an imbedded steel screw flush with the surface. The screw was 2 mm  in diameter.  I was only taking off maybe .02mm at a time, yet the screw deflected the cutter enough to cause it to dig deeper on the opposite side.  Not much, just enough to ruin the appearance of the surface.  No matter how small a cut I tried, it happened every time.  Then I put light pressure on the head of  the machine while the cutter was turning.  Even though I h ad the Z axis locked tight, and I run my gibs tight, a few ounces of pressure was all it took to tilt the head back enough to raise the fly cutter away from the surface it was cutting.  That is how flexible these machines are.

                                                I realize that at times I break some long held conventions when it comes to milling, but what I am doing is adapting my techniques  to accommodate the limitations of the mini mill.

                                                 

                                                Regards,

                                                 

                                                Robert

                                                 

                                                From: GrizHFMinimill@yahoogroups.com [mailto:GrizHFMinimill@yahoogroups.com] On Behalf Of Ian Newman
                                                Sent: Wednesday, May 15, 2013 8:17 AM
                                                To: GrizHFMinimill@yahoogroups.com
                                                Subject: Re: [GrizHFMinimill] How would YOU do this?

                                                 

                                                 

                                                Hi,

                                                 

                                                <SNIP>

                                                Use a 3/8 end mill, and make 3/8 wide cuts. I think you will find that the machine is quietest when the end mill has a large contact area with the material being cut. The reason is that there are always at least two flutes in contact with the material, while your method of using 1/3 the diameter likely has just one flute in contact, creating an alternating cycle of high loads going to near zero load, and back.

                                                </SNIP>

                                                 

                                                I would take a different view to that expressed above - depending on the type of cutter you are using.

                                                 

                                                Before I start a word about my terminology - I'm in the UK and in this part of the world an end mill is never able to centre cut, what is called a centre cutting end mill in the USA, we call a slot drill. Slot drills usually have two (sometimes three) flutes, end mills have four or more.

                                                For slot cutting, or cutting the full width of the cutter, you should not use an end mill - the four flutes make it almost impossible to cut a smooth side to the slot.

                                                To get a idea of the problem, imagine a four flute cutter cutting a slot (so it is cutting the full width of the cutter). Picture the plan view of the job, the cutter rotating clockwise and call the direction of the pass over the material the "front".

                                                As one of the cutter teeth cuts away the front of the slot, it will tend to bend the cutter to the left (looking at the plan view) and push the left hand cutter tooth into the side of the slot. This causes a very rough, lumpy and poor quality side to the slot - this is why you should not cut a slot with a end mill (or if you do, use a cutter smaller than the width of the slot that you wish to cut and cut each side of the slot separately). The two flute slot drill does not suffer from this problem as when the front of the slot is being cut and the cutter flexes, there is no other tooth in contact with the slot sides.

                                                The usual recommendation is to limit the width of the cut for an end mill to less than 1/4 of the cutter diameter of the cutter, thus minimising the sideways flexing of the cutting tool and the associated problems.

                                                Attempts to cut both sides of a slot at the same time with an end mill often results in the corner of the tooth chipping off the cutter (due to the flexing/digging in problem) - this can be avoided by stoning a small bevel on the tip of each tooth. It need not be much, just 20 to 30 thou or so.

                                                All the best,
                                                Ian.

                                                 

                                                 

                                                 

                                                From: Robert Furmanak <rfurmanak@...>
                                                To: GrizHFMinimill@yahoogroups.com
                                                Sent: Sunday, 12 May 2013, 3:35
                                                Subject: RE: [GrizHFMinimill] How would YOU do this?

                                                 

                                                Charlie

                                                 

                                                My experience is that the Mini Mill is not nearly stiff enough to use a 5/8 end mill.  It does not matter that you are only using 1/3 of the diameter, what matters is that you are putting a considerable side load on the machine with every pass the cutting edge makes.  I’m willing to bet you would make twice as much progress with a 3/8 end mill.  Also, I have found that even with the smaller end mill, there is far less vibration when using the full width of the end mill, rather than the side.  Here is how I would handle your problem.  Use a 3/8 end mill, and make 3/8 wide cuts.  I think you will find that the machine is quietest when the end mill has a large contact area with the material being cut.  The reason is that there are always at least two flutes in contact with the material, while your method of using 1/3 the diameter likely has just one flute in contact, creating an alternating cycle of high loads going to near zero load, and back.

                                                 

                                                As for climb milling, I think that has been given a bad rap.  I read a good paper on the physics of it a while ago, and climb milling is actually less stressful to the cutting edge.  The problem arises when the machine is too loose, and allows the end mill to pull itself deeper into the material.  I do all my finishing cuts as climbing cuts, and I have my machine set very tight.   When using the full width of the end mill as I suggested above, the climbing forces are held in check by the resistance the other side is experiencing.  However, with very small end mills, the mill will try to climb sideways by bending, so one has to watch for that, at 1/8 inch diameter and below.  

                                                 

                                                Robert

                                                 

                                                From: GrizHFMinimill@yahoogroups.com [mailto:GrizHFMinimill@yahoogroups.com] On Behalf Of CLevinski
                                                Sent: Saturday, May 11, 2013 4:49 PM
                                                To: GrizHFMinimill@yahoogroups.com
                                                Subject: [GrizHFMinimill] How would YOU do this?

                                                 

                                                 

                                                Hi,

                                                While I've done a number of small projects on my lathe, my mini-mill is definitely underutilized.  So I started a little project today that involves taking a 1.150 x 1.850 inch piece of aluminum I had lying around, and sizing it to make a widget.  Only problem is that it was almost 1.500 inches thick, and I need it to be 1.000 inches thick.  So I thought, "Nah, I don't need to use the band saw!  I'll just mill that puppy down.".  Almost 2 hours of continuous milling later (while wearing hearing protection, because I haven't made a belt drive conversion), it is now down to 1.250 inches.  I'm face milling with a 5/8 inch end mill, only engaging about 1/3 of the diameter, never climb milling, and cutting in all four directions.  (Essentially cutting in a counter-clockwise rectangle.)  I'm running the mini-mill fairly slowly (maybe 600 RPM?, though I tried it nearer to 900 RPM and didn't pick up any noticeable benefit except for greater swarf-throwing range).  I tried cuts from .020 to .030 inches and settled on .025 inches as maximum material removal without excess noise.

                                                I have a fly cutter set (though I've never used it) but fly cutters are primarily for finishing cuts, I understand, so I don't think that's the solution.

                                                So my question; how would YOU more experienced guys do this?  Is there a technique I'm missing that would allow me to do this faster?  Since this isn't a finishing cut, could I use the full end mill width?  That would certainly speed up the process but I read that it's bad for the end mill (specially a four-flute) since one side is conventional milling and the other side is climb milling.

                                                And yes, if I can't find a better way, I'll probably go back to the band saw and then make a couple of passes with the mill to finish the surface.

                                                Times like this, I wish I had a Bridgeport.  But I don't think I'd be able to carry it down the cellar steps... ;)

                                                Thanks,
                                                Charlie

                                                 

                                              • gerry waclawiak
                                                Robert, I am sorry if I have caused offence it was not my intention to do so but I wanted to address what I felt was an unwarranted rubbishing of the original
                                                Message 23 of 24 , May 20, 2013
                                                  Robert,
                                                  I am sorry if I have caused offence it was not my intention to do so but I wanted to address what I felt was an unwarranted rubbishing of the original X2 mills. I of course had no knowledge of our skill and experience, similarly I suggest the reverse is also true

                                                  I have had my mill for a lot of years and it has performed admirably for me on a variety of projects. At the time most of the mills on sale in the UK were versions of the Sieg X2, I only found out about RB about a year after my purchase and at that time they did not differ materially although it has always been my observation and experience that the RB models seem to be a little better made and offer some extra features. RB models are now much more common.

                                                  I am fully aware of the developement of the various mini-mills and I have never said or implied thsat the basic Sieg can match the latest models merely that I did not believe it as bad as you appeared to make out and I stand by that.

                                                  Yes the original had weaknesses and there were a string of home tweaks and improvements as a result. Many have by and large been addressed by the factories and the latest are clearly far better in many areas but that has attracted a considerable price increase and it is for the individual to decide whether they can justify the difference.

                                                  My observation over the years was that many of those criticising the X2's were those who were pushing the envelope and should perhaps have considered a larger mill in the first place. I still believe that true despite the improvements

                                                  If I had my time over I would definately be looking at one of the better models especially those with the larger table and X/Y movement but my original X2 is still going strong and doing what I want from it so I have no plans to change any time soon

                                                  Gerry W
                                                  Leeds UK



                                                  To: GrizHFMinimill@yahoogroups.com
                                                  From: rfurmanak@...
                                                  Date: Sun, 19 May 2013 22:12:59 -0400
                                                  Subject: RE: [GrizHFMinimill] How would YOU do this?

                                                   

                                                  Gerry,

                                                   

                                                      I am assuming that you have a Real Bull like most Europeans, and not a Sieg like most Americans.  While I have not had the opportunity to do a side by side comparison, from what I have seen, the Real Bulls are somewhat better in most areas.  The original Sieg models with the small table and still sold by Harbor Freight, were especially bad.  The Y axis gib had only two setscrews.  That meant that under some operating conditions, the stresses transmitted through the carriage to the base were carried by only two 6mm screws.  It was nearly impossible to work a piece which was over 6 inches above the table, say for example when I had my rotary table and 3 inch chuck mounted on the mill.  Now the lever arm working against those two screws was relatively large, and it was impossible to keep the table from flexing.  The improved Sieg mill sold by Little Machine Shop has a much larger carriage and 4 setscrews. That fixed the table flex problem, and made using the rotary table much easier.

                                                     The original Sieg column is thin.  I remember reading the story one person who lightly compressed the bottom of a Sieg column with a C clamp while measuring the compression with a caliper.  It easily compressed a few thousandths of an inch in the area where the pivot bolt goes through.  That is flexible, and any flexibility at the base is magnified by the distance the head is up the column from the base.  It is this flexibility that has prompted many users here to try things like filling the column with epoxy.

                                                     Finally, we now have a Sieg mill comparable to yours in the LMS Solid Column Hi Torque mini mill.  So, in the future, please consider these differences before making generalized statements which imply that I do not know how to operate or adjust my mill.

                                                   

                                                  Robert

                                                   

                                                  From: GrizHFMinimill@yahoogroups.com [mailto:GrizHFMinimill@yahoogroups.com] On Behalf Of gerry waclawiak
                                                  Sent: Friday, May 17, 2013 1:39 PM
                                                  To: GrizHFMinimill@yahoogroups.com
                                                  Subject: RE: [GrizHFMinimill] How would YOU do this?

                                                   

                                                   

                                                  I can only think that Robert's mill was a particularly bad example and poorly assembled and adjusted to boot.

                                                  I have had my mill for several years and other than the commonly discussed tweaks and adjustments is fundamentally stock.

                                                  I made a belt drive conversion primarily for the noise reduction (bedroom workshop) and to give a degree of protection against breakage due to the increased use of fly cutters to surface stock relatively quickly and cheaply.

                                                  I do not find the flex to be an particular issue with appropriate management and technique and due regard to the size and power of the machine

                                                  Gerry W

                                                  Leeds UK


                                                  To: GrizHFMinimill@yahoogroups.com
                                                  From: rfurmanak@...
                                                  Date: Fri, 17 May 2013 13:07:00 -0400
                                                  Subject: RE: [GrizHFMinimill] How would YOU do this?

                                                   

                                                   

                                                  Ian,

                                                   

                                                    Your advice is good, and I do not disagree with a word of it.  However, the problem needing  to be solved was rapid removal of material, not quality of the cut.

                                                  Everything you said about the tendency of an end mill to flex in a slot is correct, however I have found that to be the lesser of two evils,  with the greater evil the considerable flexibility of the Mini Mill. 

                                                   I ran a test to see how much material I could remove rapidly, in response to the original question:

                                                   

                                                  “So I started a little project today that involves taking a 1.150 x 1.850 inch piece of aluminum I had lying around, and sizing it to make a widget.  Only problem is that it was almost 1.500 inches thick, and I need it to be 1.000 inches thick.  So I thought, "Nah, I don't need to use the band saw!  I'll just mill that puppy down.".  Almost 2 hours of continuous milling later (while wearing hearing protection, because I haven't made a belt drive conversion), it is now down to 1.250 inches.”

                                                   

                                                  I used a 1/2 inch 4 flute carbide end mill, and removed 1mm of aluminum at a speed of 240 mm/min with a minimum of vibration. I used the full with of the end mill.  1.25 mm deep cuts might have been OK,  but 2 mm was definitely too much.

                                                  It took me 4 minutes to remove 5.5 mm from a 64 x 19 mm block.  At that rate, I could have milled the  29.2 x 47mm block mentioned above down 12.7mm in about 12 minutes, instead of 4 hours.   

                                                   

                                                  The Mini Mill is so flexible that end mill flexibility is only a factor below ¼ inch.  I have now modified my Mini Mill with a solid column and large table.  Now it is maybe 10 times better than my original mill.  

                                                  The other day,  I was surfacing a piece of aluminum with a ¾ inch carbide facing tool.  The aluminum had an imbedded steel screw flush with the surface. The screw was 2 mm  in diameter.  I was only taking off maybe .02mm at a time, yet the screw deflected the cutter enough to cause it to dig deeper on the opposite side.  Not much, just enough to ruin the appearance of the surface.  No matter how small a cut I tried, it happened every time.  Then I put light pressure on the head of  the machine while the cutter was turning.  Even though I h ad the Z axis locked tight, and I run my gibs tight, a few ounces of pressure was all it took to tilt the head back enough to raise the fly cutter away from the surface it was cutting.  That is how flexible these machines are.

                                                  I realize that at times I break some long held conventions when it comes to milling, but what I am doing is adapting my techniques  to accommodate the limitations of the mini mill.

                                                   

                                                  Regards,

                                                   

                                                  Robert

                                                   

                                                  From: GrizHFMinimill@yahoogroups.com [mailto:GrizHFMinimill@yahoogroups.com] On Behalf Of Ian Newman
                                                  Sent: Wednesday, May 15, 2013 8:17 AM
                                                  To: GrizHFMinimill@yahoogroups.com
                                                  Subject: Re: [GrizHFMinimill] How would YOU do this?

                                                   

                                                   

                                                  Hi,

                                                   

                                                  <SNIP>

                                                  Use a 3/8 end mill, and make 3/8 wide cuts. I think you will find that the machine is quietest when the end mill has a large contact area with the material being cut. The reason is that there are always at least two flutes in contact with the material, while your method of using 1/3 the diameter likely has just one flute in contact, creating an alternating cycle of high loads going to near zero load, and back.

                                                  </SNIP>

                                                   

                                                  I would take a different view to that expressed above - depending on the type of cutter you are using.

                                                   

                                                  Before I start a word about my terminology - I'm in the UK and in this part of the world an end mill is never able to centre cut, what is called a centre cutting end mill in the USA, we call a slot drill. Slot drills usually have two (sometimes three) flutes, end mills have four or more.

                                                  For slot cutting, or cutting the full width of the cutter, you should not use an end mill - the four flutes make it almost impossible to cut a smooth side to the slot.

                                                  To get a idea of the problem, imagine a four flute cutter cutting a slot (so it is cutting the full width of the cutter). Picture the plan view of the job, the cutter rotating clockwise and call the direction of the pass over the material the "front".

                                                  As one of the cutter teeth cuts away the front of the slot, it will tend to bend the cutter to the left (looking at the plan view) and push the left hand cutter tooth into the side of the slot. This causes a very rough, lumpy and poor quality side to the slot - this is why you should not cut a slot with a end mill (or if you do, use a cutter smaller than the width of the slot that you wish to cut and cut each side of the slot separately). The two flute slot drill does not suffer from this problem as when the front of the slot is being cut and the cutter flexes, there is no other tooth in contact with the slot sides.

                                                  The usual recommendation is to limit the width of the cut for an end mill to less than 1/4 of the cutter diameter of the cutter, thus minimising the sideways flexing of the cutting tool and the associated problems.

                                                  Attempts to cut both sides of a slot at the same time with an end mill often results in the corner of the tooth chipping off the cutter (due to the flexing/digging in problem) - this can be avoided by stoning a small bevel on the tip of each tooth. It need not be much, just 20 to 30 thou or so.

                                                  All the best,
                                                  Ian.

                                                   

                                                   

                                                   

                                                  From: Robert Furmanak <rfurmanak@...>
                                                  To: GrizHFMinimill@yahoogroups.com
                                                  Sent: Sunday, 12 May 2013, 3:35
                                                  Subject: RE: [GrizHFMinimill] How would YOU do this?

                                                   

                                                  Charlie

                                                   

                                                  My experience is that the Mini Mill is not nearly stiff enough to use a 5/8 end mill.  It does not matter that you are only using 1/3 of the diameter, what matters is that you are putting a considerable side load on the machine with every pass the cutting edge makes.  I’m willing to bet you would make twice as much progress with a 3/8 end mill.  Also, I have found that even with the smaller end mill, there is far less vibration when using the full width of the end mill, rather than the side.  Here is how I would handle your problem.  Use a 3/8 end mill, and make 3/8 wide cuts.  I think you will find that the machine is quietest when the end mill has a large contact area with the material being cut.  The reason is that there are always at least two flutes in contact with the material, while your method of using 1/3 the diameter likely has just one flute in contact, creating an alternating cycle of high loads going to near zero load, and back.

                                                   

                                                  As for climb milling, I think that has been given a bad rap.  I read a good paper on the physics of it a while ago, and climb milling is actually less stressful to the cutting edge.  The problem arises when the machine is too loose, and allows the end mill to pull itself deeper into the material.  I do all my finishing cuts as climbing cuts, and I have my machine set very tight.   When using the full width of the end mill as I suggested above, the climbing forces are held in check by the resistance the other side is experiencing.  However, with very small end mills, the mill will try to climb sideways by bending, so one has to watch for that, at 1/8 inch diameter and below.  

                                                   

                                                  Robert

                                                   

                                                  From: GrizHFMinimill@yahoogroups.com [mailto:GrizHFMinimill@yahoogroups.com] On Behalf Of CLevinski
                                                  Sent: Saturday, May 11, 2013 4:49 PM
                                                  To: GrizHFMinimill@yahoogroups.com
                                                  Subject: [GrizHFMinimill] How would YOU do this?

                                                   

                                                   

                                                  Hi,

                                                  While I've done a number of small projects on my lathe, my mini-mill is definitely underutilized.  So I started a little project today that involves taking a 1.150 x 1.850 inch piece of aluminum I had lying around, and sizing it to make a widget.  Only problem is that it was almost 1.500 inches thick, and I need it to be 1.000 inches thick.  So I thought, "Nah, I don't need to use the band saw!  I'll just mill that puppy down.".  Almost 2 hours of continuous milling later (while wearing hearing protection, because I haven't made a belt drive conversion), it is now down to 1.250 inches.  I'm face milling with a 5/8 inch end mill, only engaging about 1/3 of the diameter, never climb milling, and cutting in all four directions.  (Essentially cutting in a counter-clockwise rectangle.)  I'm running the mini-mill fairly slowly (maybe 600 RPM?, though I tried it nearer to 900 RPM and didn't pick up any noticeable benefit except for greater swarf-throwing range).  I tried cuts from .020 to .030 inches and settled on .025 inches as maximum material removal without excess noise.

                                                  I have a fly cutter set (though I've never used it) but fly cutters are primarily for finishing cuts, I understand, so I don't think that's the solution.

                                                  So my question; how would YOU more experienced guys do this?  Is there a technique I'm missing that would allow me to do this faster?  Since this isn't a finishing cut, could I use the full end mill width?  That would certainly speed up the process but I read that it's bad for the end mill (specially a four-flute) since one side is conventional milling and the other side is climb milling.

                                                  And yes, if I can't find a better way, I'll probably go back to the band saw and then make a couple of passes with the mill to finish the surface.

                                                  Times like this, I wish I had a Bridgeport.  But I don't think I'd be able to carry it down the cellar steps... ;)

                                                  Thanks,
                                                  Charlie

                                                   


                                                • johann_ohnesorg
                                                  I completely agree with Mike but would use my 4x6 bandsaw for this. The mini mill should be sold as a combo with the 4x6 One can cut 0,04 thick slices from
                                                  Message 24 of 24 , May 20, 2013
                                                    I completely agree with Mike but would use my 4x6" bandsaw for this. The mini mill should be sold as a combo with the 4x6"
                                                    One can cut 0,04" thick slices from stock with a blueprinted 4x6"

                                                    Apart form that, if I have to make huge aluminum or steel parts, I remove a lot of material with shallow cuts with a 1" face mill with 2 carbide inserts cutter and maximum RPM. The main thing is that the chips have a place to go so the cutter should be a little bit wider than the part. Shallow means 0,02" to 0,04"
                                                    Sounds like nothing but one can crank as fast as possible and the chips will fly blue and hot. So with a few passes, one would be at the end measure.
                                                    But to do this, one needs carbide for steel. In aluminum, HSS/M2 would be good enough.

                                                    The mini is a quite capable machine with a good vise, sharp tools and the belt mod, wouldn´t like to give mine away.

                                                    Cheers,
                                                    Johann



                                                    ------------------------------------------------
                                                    > I would cut it with a hacksaw first about 1/16" from the line. Then mill the rest by side milling. I get better results side milling the face milling with an endmill.
                                                    > mike
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