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Re: 3 1/2" hole

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  • miker557
    If the hole needs to be precise in size, then the way to go would be to drill it out about 3 using a bi-metal hole saw, then using a boring head to do the
    Message 1 of 15 , Dec 6, 2006
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      If the hole needs to be precise in size, then the way to go would be
      to drill it out about 3" using a bi-metal hole saw, then using a
      boring head to do the rest. If some varience is allowed in the final
      size, then the 3 1/2" hole saw would be the way to go, considering
      time and money. Just go slow and use LOTS of cutting fluid (TapMagic
      is my favorite).


      Miker
    • Jerry Kimberlin
      ... A carbide toothed hole saw might do it if you don t go to fast and get chatter. I don t know about a bimetal holesaw. I ve used plain holesaws on
      Message 2 of 15 , Dec 6, 2006
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        mark wrote:
        > I will have to say no. I have one, but it is set up and being used as
        > a jig and tooling, and I can't knock it down. If I did, I guess I
        > could work with end mills, but I need other options.
        A carbide toothed hole saw might do it if you don't go to fast and get
        chatter. I don't know about a bimetal holesaw. I've used plain
        holesaws on aluminum and that works OK.

        You could also chain drill a circle and file to the line. Better would
        be to chain drill then use a boring head to finish to size. A hole saw
        followed by a boring head to size is probably what I'd do.

        Another idea would be to flame cut it, but that assumes you don't need
        it very accurate - just a hole.

        JerryK
      • mark
        ... be ... final ... (TapMagic ... Thanks Miker, Any recommendations on rpm s for the holesaw? Any recommendations on the boring head. The boring head might be
        Message 3 of 15 , Dec 6, 2006
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          --- In mill_drill@yahoogroups.com, "miker557" <mikaelc@...> wrote:
          >
          > If the hole needs to be precise in size, then the way to go would
          be
          > to drill it out about 3" using a bi-metal hole saw, then using a
          > boring head to do the rest. If some varience is allowed in the
          final
          > size, then the 3 1/2" hole saw would be the way to go, considering
          > time and money. Just go slow and use LOTS of cutting fluid
          (TapMagic
          > is my favorite).
          >
          >
          > Miker

          Thanks Miker,

          Any recommendations on rpm's for the holesaw? Any recommendations on
          the boring head. The boring head might be nice to have for future
          use, and you can never have enough toys. The hole doesn't need to be
          precise, but good machining is always nice to see.

          Mark
        • Bill Pace
          What I DO know about getting large holes is they are usually a heartache for me. My very 1st choice would be to do the chain drilling method and then clean up
          Message 4 of 15 , Dec 6, 2006
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            What I DO know about getting large holes is they are usually a
            heartache for me. My very 1st choice would be to do the chain
            drilling method and then clean up with the boring head/bar, but you
            say your table is tied up....... I,ve used up to about 2 1/2" hole
            saw on al and it was a struggle--takes a LOT of power as it gets down
            deeper, boy, I have trouble picturing going through --was it 5/8" and
            3 1/2 dia, yow!! I havent ever had one of the carbide tipped saws and
            that may make all the difference...I too think it'll take a lot of
            lube. If you gotta buy a boring head to reach 3 1/2" its gonna be a
            bit pricy, a quick glance in WT's catalogue shows one at $199 and
            another at $159.

            Let us know how you work this out!!

            Bill


            --- In mill_drill@yahoogroups.com, "mark" <gmiller4396@...> wrote:
            >
            > --- In mill_drill@yahoogroups.com, "miker557" <mikaelc@> wrote:
            > >
            > > If the hole needs to be precise in size, then the way to go would
            > be
            > > to drill it out about 3" using a bi-metal hole saw, then using a
            > > boring head to do the rest. If some varience is allowed in the
            > final
            > > size, then the 3 1/2" hole saw would be the way to go,
            considering
            > > time and money. Just go slow and use LOTS of cutting fluid
            > (TapMagic
            > > is my favorite).
            > >
            > >
            > > Miker
            >
            > Thanks Miker,
            >
            > Any recommendations on rpm's for the holesaw? Any recommendations
            on
            > the boring head. The boring head might be nice to have for future
            > use, and you can never have enough toys. The hole doesn't need to
            be
            > precise, but good machining is always nice to see.
            >
            > Mark
            >
          • Rexarino
            Mark, I ve cut holes in steel with holesaws with good results. If I can, I always drill a hole in the waste side of the material for chips to clear the saw
            Message 5 of 15 , Dec 6, 2006
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              Mark, I've cut holes in steel with holesaws with good results.  If I can, I always drill a hole in the waste side of the material for chips to clear the saw teeth.  In your case, I'd drill one or two 3/8+ inch holes tangent to the inside of the circle, for swarf to fall into.  I like sulphur based cutting oil for steel, but most light oils and cutting fluids work fine.

              The slower the speed, the longer the tool will last, down to 15 - 20 rpm.  I've run at 30 - 50 rpm with a saw and didn't destroy the saw.  Most of the time, I've experimented and found a speed that seems to have the least vibration and the best cut.  Don't be afraid to feed sorta aggressively, it seems to help - as long as the saw doesn't get hot - lotsa coolant helps.  Get a helper to keep the coolant/cutting oil running.

              Sometimes the pilot drill wants to wallow out a big hole in the center, which makes everything vibrate and run oversize.  If that happens, I have a 1/4 inch rod I substitute for the pilot, after I predrill the pilot hole.

              Remember those ultra cheap 9 in 1 hole saws that all came on the same spindle?  I actually made one of those cut through a porcelain enamel sink - the kind you're supposed to use a diamond drill on - by using high pressure, slow speed, and running water for a coolant.

              Good luck



              On 12/6/06, mark < gmiller4396@... > wrote:
              I have four pieces of steel plate that are 8x11x5/16 and I need to bore
              or drill a 3 1/2" hole in each one of them. I was thinking that  3 1/2"
              bi-metal holesaw would work for me. If I can get two holes out of a
              saw, I would be ok with the cost. Any other suggestions for a mill
              cutter and where to get it? I have a HF 33686 2hp mill.

              Mark




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              --
              How much easier it is to be critical than to be correct.
                - Benjamin Disraeli
            • Jerry Kimberlin
              ... 3 1/2 is quite a reach for the normal cheapy Criterion or its Enco clone. I have done it, but just barely and with very little material being taken off
              Message 6 of 15 , Dec 6, 2006
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                Bill Pace wrote:
                > If you gotta buy a boring head to reach 3 1/2" its gonna be a
                > bit pricy, a quick glance in WT's catalogue shows one at $199 and
                > another at $159.
                3 1/2" is quite a reach for the normal cheapy Criterion or its Enco
                clone. I have done it, but just barely and with very little material
                being taken off at each pass. I also would do chain drilling rather
                than try the hole cutter mainly because I don't have carbide toothed
                hold cutters, which are quite expensive and take a lot of power to use.

                The nice thing is that if you are doing 4 plates 5/16" thick, you can
                dowel or bolt them together and do the final finishing of all of them in
                a stack with the boring head. If it is important to get all of the
                plates identical, then line boring them with a boring head is the best way.

                An alternative to a boring head is a purpose built fly cutter that is
                non adjustable. This would be easy enough to build but wouldn't be
                nearly as utilitarian as just springing for the cost of a real
                adjustable boring head. Actually Enco has one for $105 that will do the
                job:
                http://www.use-enco.com/CGI/INSRIT?PARTPG=INSRAR2&PMAKA=223-1150&PMPXNO=951669
                #223-1150 $105.45. And there is free shipping - HPFS6 in the promo code.

                JerryK
              • Warren Fowler
                I made a circle cutter,similar to one used in wood,for cutting a 3.250 holes in Aluminum.Slow rpm and I like Rapid Tap for a cutting fluid.I can send a
                Message 7 of 15 , Dec 6, 2006
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                  I  made a circle cutter,similar to one used in wood,for cutting a 3.250 holes in Aluminum.Slow rpm and I like Rapid Tap for a cutting fluid.I can send a picture if you would like.Warren
                  ----- Original Message -----
                  From: Rexarino
                  Sent: Wednesday, December 06, 2006 10:16 PM
                  Subject: Re: [mill_drill] 3 1/2" hole

                  Mark, I've cut holes in steel with holesaws with good results.  If I can, I always drill a hole in the waste side of the material for chips to clear the saw teeth.  In your case, I'd drill one or two 3/8+ inch holes tangent to the inside of the circle, for swarf to fall into.  I like sulphur based cutting oil for steel, but most light oils and cutting fluids work fine.

                  The slower the speed, the longer the tool will last, down to 15 - 20 rpm.  I've run at 30 - 50 rpm with a saw and didn't destroy the saw.  Most of the time, I've experimented and found a speed that seems to have the least vibration and the best cut.  Don't be afraid to feed sorta aggressively, it seems to help - as long as the saw doesn't get hot - lotsa coolant helps.  Get a helper to keep the coolant/cutting oil running.

                  Sometimes the pilot drill wants to wallow out a big hole in the center, which makes everything vibrate and run oversize.  If that happens, I have a 1/4 inch rod I substitute for the pilot, after I predrill the pilot hole.

                  Remember those ultra cheap 9 in 1 hole saws that all came on the same spindle?  I actually made one of those cut through a porcelain enamel sink - the kind you're supposed to use a diamond drill on - by using high pressure, slow speed, and running water for a coolant.

                  Good luck



                  On 12/6/06, mark < gmiller4396@ yahoo.com > wrote:
                  I have four pieces of steel plate that are 8x11x5/16 and I need to bore
                  or drill a 3 1/2" hole in each one of them. I was thinking that  3 1/2"
                  bi-metal holesaw would work for me. If I can get two holes out of a
                  saw, I would be ok with the cost. Any other suggestions for a mill
                  cutter and where to get it? I have a HF 33686 2hp mill.

                  Mark




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                  --
                  How much easier it is to be critical than to be correct.
                    - Benjamin Disraeli

                • SupportOurTroops - Skip
                  Trepanning tools are great for cutting holes or discs. I have a Val-Cut model 2000 (smaller) and use it frequently cutting 2 1/2 holes in 3/8 aluminum plate.
                  Message 8 of 15 , Dec 6, 2006
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                    Trepanning tools are great for cutting holes or discs. I have a Val-Cut
                    model 2000 (smaller) and use it frequently cutting 2 1/2" holes in
                    3/8" aluminum plate. The 3000 model would probably be better for
                    what you are doing. JTS has them. Rather expensive but well worth
                    it in my opinion, especially if you are making money on the holes
                    or discs.
                    http://www.jtsmach.com/jtswebshop/Pr_CuttingTools/D317.asp

                    This tool is even more pleasurable to use now that I have the dc
                    motor on my mill. I can easily adjust the speed on the fly to eliminate
                    any chatter in any operation. The trepanning tool presents the least
                    chattering problems of any operation that I have done. The trailing
                    angle of the cutter is what keeps chatter down to a minimum.

                    Skip Campbell
                    (I have a nice 3/4 HP DC motor/controller/digital tach unit for sale)
                  • j.c.gerber
                    Hi Skip You are right, this Swiss made Val-Cut trepanning tools are of high quality. I recently used a Far East one I received from a chap. It took a few turns
                    Message 9 of 15 , Dec 6, 2006
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                      Hi Skip
                       
                      You are right, this Swiss made Val-Cut trepanning tools are of high quality. I recently used a Far East one I received from a chap. It took a few turns and it was bent. This poor tool looked good but was not even hardened!
                       
                      Jean-Claude, Switzerland
                      www.homestead.com/turnandmill
                       
                      ----- Original Message -----
                      Sent: Thursday, December 07, 2006 7:17 AM
                      Subject: Re: [mill_drill] Re: 3 1/2" hole

                      Trepanning tools are great for cutting holes or discs. I have a Val-Cut
                      model 2000 (smaller) and use it frequently cutting 2 1/2" holes in
                      3/8" aluminum plate. The 3000 model would probably be better for
                      what you are doing. JTS has them. Rather expensive but well worth
                      it in my opinion, especially if you are making money on the holes
                      or discs.
                      http://www.jtsmach. com/jtswebshop/ Pr_CuttingTools/ D317.asp

                      This tool is even more pleasurable to use now that I have the dc
                      motor on my mill. I can easily adjust the speed on the fly to eliminate
                      any chatter in any operation. The trepanning tool presents the least
                      chattering problems of any operation that I have done. The trailing
                      angle of the cutter is what keeps chatter down to a minimum.

                      Skip Campbell
                      (I have a nice 3/4 HP DC motor/controller/ digital tach unit for sale)

                    • accuratemike
                      Skip, I d post that 3/4 HP DC stuff on the 9x20lathe group. Hot item there. (I m a 3ph/VFD guy myself) MIKE
                      Message 10 of 15 , Dec 7, 2006
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                        Skip, I'd post that 3/4 HP DC stuff on the 9x20lathe group. Hot item
                        there. (I'm a 3ph/VFD guy myself) MIKE

                        --- In mill_drill@yahoogroups.com, SupportOurTroops - Skip
                        <mkc1951@...> wrote:
                        >
                        > Trepanning tools are great for cutting holes or discs. I have a Val-Cut
                        > model 2000 (smaller) and use it frequently cutting 2 1/2" holes in
                        > 3/8" aluminum plate. The 3000 model would probably be better for
                        > what you are doing. JTS has them. Rather expensive but well worth
                        > it in my opinion, especially if you are making money on the holes
                        > or discs.
                        > http://www.jtsmach.com/jtswebshop/Pr_CuttingTools/D317.asp
                        >
                        > This tool is even more pleasurable to use now that I have the dc
                        > motor on my mill. I can easily adjust the speed on the fly to eliminate
                        > any chatter in any operation. The trepanning tool presents the least
                        > chattering problems of any operation that I have done. The trailing
                        > angle of the cutter is what keeps chatter down to a minimum.
                        >
                        > Skip Campbell
                        > (I have a nice 3/4 HP DC motor/controller/digital tach unit for sale)
                        >
                      • n5kzw
                        ... SNIP ... My cheapy Asian boring bar holder has the provision to mount the boring bar horizonally, as well as vertically. In that orientation, the head
                        Message 11 of 15 , Dec 7, 2006
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                          --- In mill_drill@yahoogroups.com, Jerry Kimberlin <kimberln@...> wrote:
                          >
                          > Bill Pace wrote:
                          > > If you gotta buy a boring head to reach 3 1/2" its gonna be a
                          > > bit pricy, a quick glance in WT's catalogue shows one at $199 and
                          > > another at $159.
                          > 3 1/2" is quite a reach for the normal cheapy Criterion or its Enco
                          > clone. I have done it, but just barely and with very little material
                          > being taken off at each pass.
                          SNIP>
                          >
                          > JerryK
                          >
                          My cheapy Asian boring bar holder has the provision to mount the
                          boring bar horizonally, as well as vertically. In that orientation,
                          the head would not have to be extended very far, even with a short
                          boring bar. It might be necessary to use a HSS boring bar to get the
                          angles ground correctly for that orientation, and light cuts would
                          probably still be needed.

                          Regards,
                          Ed
                        • lathe9x20
                          Skip -- What is the shape of the bit on one of those? I have one (from Enco IIRC), but haven t been able discover a bit shape that works for deep holes (e.g.
                          Message 12 of 15 , Dec 7, 2006
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                            Skip --

                            What is the shape of the bit on one of those? I have one (from Enco
                            IIRC), but haven't been able discover a bit shape that works for deep
                            holes (e.g. 1/2 inch).

                            Looking from the bottom of the bit, the end must be triangular, right?
                            With the leading edge the base of the triangle, and perhaps the side
                            closest to the center of the circle about 90 to the leading edge?
                            What are the approximate angles of the bit, looking from the bottom?

                            Also, is the leading edge parallel to a radius?

                            I assume the rake on the rake (looking from the side at the bit) is
                            whatever is appropriate for the material, 0 degrees for brass, 7-10
                            for or steel, more for AL.

                            Thanks

                            John


                            --- In mill_drill@yahoogroups.com, SupportOurTroops - Skip
                            <mkc1951@...> wrote:
                            >
                            > Trepanning tools are great for cutting holes or discs. I have a Val-Cut
                            > model 2000 (smaller) and use it frequently cutting 2 1/2" holes in
                            > 3/8" aluminum plate. The 3000 model would probably be better for
                            > what you are doing. JTS has them. Rather expensive but well worth
                            > it in my opinion, especially if you are making money on the holes
                            > or discs.
                            > http://www.jtsmach.com/jtswebshop/Pr_CuttingTools/D317.asp
                            >
                            > This tool is even more pleasurable to use now that I have the dc
                            > motor on my mill. I can easily adjust the speed on the fly to eliminate
                            > any chatter in any operation. The trepanning tool presents the least
                            > chattering problems of any operation that I have done. The trailing
                            > angle of the cutter is what keeps chatter down to a minimum.
                            >
                            > Skip Campbell
                            > (I have a nice 3/4 HP DC motor/controller/digital tach unit for sale)
                            >
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