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RE: [atlas_craftsman] Grinding BIts

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  • Robert Hyland
    DW, A tip that I use when free handing HSS or carbide tool bits on a wheel. File a groove in both the upper and lower holding face of the vice grip, trying to
    Message 1 of 17 , Sep 5, 2011
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      DW,

      A tip that I use when free handing HSS or carbide tool bits on a wheel. File
      a groove in both the upper and lower holding face of the vice grip, trying
      to get approximately the same radius as the tool bit you are holding. That
      keeps it from rotating in the flat jaws, and gives you finer control of the
      angles which you are feeding the bit to the wheel.



      Robert in Tacoma

      From: atlas_craftsman@yahoogroups.com
      [mailto:atlas_craftsman@yahoogroups.com] On Behalf Of dws
      Sent: Monday, September 05, 2011 6:13 AM
      To: atlas_craftsman@yahoogroups.com
      Subject: [atlas_craftsman] Grinding BIts





      Thanks to Rick for the really informative reports.
      I've been grinding bits lately, and enjoying the power of getting
      whatever I'd like. Any thoughts on:
      1. How hot can HSS get before being damaged? For a long time, I was
      scared to get it red. But that made grinding a real chore, very slow.
      Then I just gave it a try. Let it get to red right on the cutting edge,
      then quench. They seem to survive. The bluish patina comes off with a
      wire wheel. The resulting cut works and looks better for having been
      ground as one long push.
      2. How to hold the bit while grinding? I have a small blister on inside
      of index finger showing the danger of just holding it purely by hand. A
      vise grip works, imperfectly, if the bit is held crosswise and gripped
      diagonally.
      3. "why not" silicon carbide (green) for HSS? They say use AO. My SC
      wheel is softer, and thus more consumed by grinding than the AO wheel
      but it seems to grind ok. SC tends to cost a bit more, purely
      economics? One quickly learns why SC is better for grinding carbide,
      but not the other way around.
      4. Any tips on rounding the tip? I can get it intuitively, just rotate
      it around a bit while at the right angle, but I'm still not very good at
      it. Right side up or upside down? Finer wheel?

      Lastly, could repliers PLEASE trim off most of the stuff being replied
      to? Today's digest was near totally unreadable, being well over 90%
      repeated stuff with only isolated replies.
      Thanks,dw

      [Non-text portions of this message have been removed]





      [Non-text portions of this message have been removed]
    • Richard Schaal
      Hi Rick, Could you post the links to your library of articles occasionally?  Like maybe monthly?  I find them really educational, and although I try to
      Message 2 of 17 , Sep 5, 2011
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        Hi Rick,

        Could you post the links to your library of articles occasionally?  Like maybe monthly?  I find them really educational, and although I try to follow some conversations on the list, it's difficult to tell if I have the latest revisions of the articles.

        The photos and diagrams you're presenting really clarify the point for me.

        Best!

        - Richard Schaal



        ________________________________
        From: RG Sparber <rgsparber@...>
        To: atlas_craftsman@yahoogroups.com
        Sent: Monday, September 5, 2011 7:06 AM
        Subject: RE: [atlas_craftsman] Grinding BIts


         
        JT,

        I guess I get away with a water dunk because I grind until it is
        uncomfortable to hold. I've never had an edge crumble on me.

        Most of my grinding is to sharpen an existing edge. The real problem for me
        is when I hog. That is when I would save a lot of time holding the blank in
        a clamp and letting it get really hot. That is when I must behave and not
        dunk the glowing cutter in water.

        I actually would not need an elaborate fixture, just something to protect my
        fingers. I still would want to do my final grinding at a much lower
        temperature.

        Thanks for the good info!

        Rick

        -----Original Message-----
        From: atlas_craftsman@yahoogroups.com
        [mailto:atlas_craftsman@yahoogroups.com] On Behalf Of jerdal@...
        Sent: Monday, September 05, 2011 6:20 AM
        To: atlas_craftsman@yahoogroups.com
        Subject: Re: [atlas_craftsman] Grinding BIts

        HSS is not damaged by being hot. It has the property of 'red hardness",
        which means it is still hard when at some degree of red heat.

        In fact, it is difficult to anneal HSS, most ordinary cooling rates will
        harden it. There is a special cooling time/temperature profile to anneal
        it.

        it IS however, possible to damage it by quenching too fast, such as in
        water. The edge can develop small cracks, and it will then tend to
        "crumble" under cutting pressure.

        JT




        [Non-text portions of this message have been removed]
      • RG Sparber
        Richard, I m always looking for new ways to share what I have written but I m not sure what you are suggesting. When a new article comes out, I share them with
        Message 3 of 17 , Sep 5, 2011
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          Richard,

          I'm always looking for new ways to share what I have written but I'm not sure what you are suggesting.

          When a new article comes out, I share them with various Yahoo groups. If the subject has nothing to do with lathes for example, I do not tend to share them with atlas_craftsman. Often, but not always, I will update an article and announce the change. It depends on what has changed.

          The home page for my site is Rick.Sparber.org. Can you give me an example of what you would like to see.

          Thanks,

          Rick

          -----Original Message-----
          From: atlas_craftsman@yahoogroups.com [mailto:atlas_craftsman@yahoogroups.com] On Behalf Of Richard Schaal
          Sent: Monday, September 05, 2011 11:49 AM
          To: atlas_craftsman@yahoogroups.com
          Subject: [atlas_craftsman] Super Articles...

          Hi Rick,

          Could you post the links to your library of articles occasionally? Like maybe monthly? I find them really educational, and although I try to follow some conversations on the list, it's difficult to tell if I have the latest revisions of the articles.

          The photos and diagrams you're presenting really clarify the point for me.

          Best!

          - Richard Schaal



          ________________________________
          From: RG Sparber <rgsparber@...>
          To: atlas_craftsman@yahoogroups.com
          Sent: Monday, September 5, 2011 7:06 AM
          Subject: RE: [atlas_craftsman] Grinding BIts



          JT,

          I guess I get away with a water dunk because I grind until it is
          uncomfortable to hold. I've never had an edge crumble on me.

          Most of my grinding is to sharpen an existing edge. The real problem for me
          is when I hog. That is when I would save a lot of time holding the blank in
          a clamp and letting it get really hot. That is when I must behave and not
          dunk the glowing cutter in water.

          I actually would not need an elaborate fixture, just something to protect my
          fingers. I still would want to do my final grinding at a much lower
          temperature.

          Thanks for the good info!

          Rick

          -----Original Message-----
          From: atlas_craftsman@yahoogroups.com
          [mailto:atlas_craftsman@yahoogroups.com] On Behalf Of jerdal@...
          Sent: Monday, September 05, 2011 6:20 AM
          To: atlas_craftsman@yahoogroups.com
          Subject: Re: [atlas_craftsman] Grinding BIts

          HSS is not damaged by being hot. It has the property of 'red hardness",
          which means it is still hard when at some degree of red heat.

          In fact, it is difficult to anneal HSS, most ordinary cooling rates will
          harden it. There is a special cooling time/temperature profile to anneal
          it.

          it IS however, possible to damage it by quenching too fast, such as in
          water. The edge can develop small cracks, and it will then tend to
          "crumble" under cutting pressure.

          JT




          [Non-text portions of this message have been removed]



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        • James Walther
          Great thread! I use the straight toolholder from my lantern toolpost to hold HSS blanks when grinding if it s anything more than a quick touch-up. From: Robert
          Message 4 of 17 , Sep 5, 2011
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            Great thread! I use the straight toolholder from my lantern toolpost to hold HSS blanks when grinding if it's anything more than a quick touch-up.


            From: Robert Hyland <roberthyland@...>
            >To: atlas_craftsman@yahoogroups.com
            >Sent: Monday, September 5, 2011 10:42 AM
            >Subject: RE: [atlas_craftsman] Grinding BIts
            >
            >
            >  
            >
            >DW,
            >
            >A tip that I use when free handing HSS or carbide tool bits on a wheel. File
            >a groove in both the upper and lower holding face of the vice grip, trying
            >to get approximately the same radius as the tool bit you are holding. That
            >keeps it from rotating in the flat jaws, and gives you finer control of the
            >angles which you are feeding the bit to the wheel.
            >
            >Robert in Tacoma
            >
            >From: atlas_craftsman@yahoogroups.com
            >[mailto:atlas_craftsman@yahoogroups.com] On Behalf Of dws
            >Sent: Monday, September 05, 2011 6:13 AM
            >To: atlas_craftsman@yahoogroups.com
            >Subject: [atlas_craftsman] Grinding BIts
            >
            >Thanks to Rick for the really informative reports.
            >I've been grinding bits lately, and enjoying the power of getting
            >whatever I'd like. Any thoughts on:
            >1. How hot can HSS get before being damaged? For a long time, I was
            >scared to get it red. But that made grinding a real chore, very slow.
            >Then I just gave it a try. Let it get to red right on the cutting edge,
            >then quench. They seem to survive. The bluish patina comes off with a
            >wire wheel. The resulting cut works and looks better for having been
            >ground as one long push.
            >2. How to hold the bit while grinding? I have a small blister on inside
            >of index finger showing the danger of just holding it purely by hand. A
            >vise grip works, imperfectly, if the bit is held crosswise and gripped
            >diagonally.
            >3. "why not" silicon carbide (green) for HSS? They say use AO. My SC
            >wheel is softer, and thus more consumed by grinding than the AO wheel
            >but it seems to grind ok. SC tends to cost a bit more, purely
            >economics? One quickly learns why SC is better for grinding carbide,
            >but not the other way around.
            >4. Any tips on rounding the tip? I can get it intuitively, just rotate
            >it around a bit while at the right angle, but I'm still not very good at
            >it. Right side up or upside down? Finer wheel?
            >
            >Lastly, could repliers PLEASE trim off most of the stuff being replied
            >to? Today's digest was near totally unreadable, being well over 90%
            >repeated stuff with only isolated replies.
            >Thanks,dw
            >
            >[Non-text portions of this message have been removed]
            >
            >[Non-text portions of this message have been removed]
            >
            >
            >
            >
            >

            [Non-text portions of this message have been removed]
          • Richard Schaal
            Rick,  I hadn t looked at your website in depth.  But I will from now on.  I didn t realize that you had so much infrastructure already established. --
            Message 5 of 17 , Sep 5, 2011
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              Rick, 


              I hadn't looked at your website in depth.  But I will from now on.  I didn't realize that you had so much infrastructure already established. -- Nice!


              Regards,
              Richard



              ________________________________
              From: RG Sparber <rgsparber@...>
              To: atlas_craftsman@yahoogroups.com
              Sent: Monday, September 5, 2011 12:32 PM
              Subject: RE: [atlas_craftsman] Super Articles...


               
              Richard,

              I'm always looking for new ways to share what I have written but I'm not sure what you are suggesting.

              When a new article comes out, I share them with various Yahoo groups. If the subject has nothing to do with lathes for example, I do not tend to share them with atlas_craftsman. Often, but not always, I will update an article and announce the change. It depends on what has changed.

              The home page for my site is Rick.Sparber.org. Can you give me an example of what you would like to see.

              Thanks,

              Rick

              -----Original Message-----
              From: atlas_craftsman@yahoogroups.com [mailto:atlas_craftsman@yahoogroups.com] On Behalf Of Richard Schaal
              Sent: Monday, September 05, 2011 11:49 AM
              To: atlas_craftsman@yahoogroups.com
              Subject: [atlas_craftsman] Super Articles...

              Hi Rick,

              Could you post the links to your library of articles occasionally? Like maybe monthly? I find them really educational, and although I try to follow some conversations on the list, it's difficult to tell if I have the latest revisions of the articles.

              The photos and diagrams you're presenting really clarify the point for me.

              Best!

              - Richard Schaal

              ________________________________
              From: RG Sparber <rgsparber@...>
              To: atlas_craftsman@yahoogroups.com
              Sent: Monday, September 5, 2011 7:06 AM
              Subject: RE: [atlas_craftsman] Grinding BIts

              JT,

              I guess I get away with a water dunk because I grind until it is
              uncomfortable to hold. I've never had an edge crumble on me.

              Most of my grinding is to sharpen an existing edge. The real problem for me
              is when I hog. That is when I would save a lot of time holding the blank in
              a clamp and letting it get really hot. That is when I must behave and not
              dunk the glowing cutter in water.

              I actually would not need an elaborate fixture, just something to protect my
              fingers. I still would want to do my final grinding at a much lower
              temperature.

              Thanks for the good info!

              Rick

              -----Original Message-----
              From: atlas_craftsman@yahoogroups.com
              [mailto:atlas_craftsman@yahoogroups.com] On Behalf Of jerdal@...
              Sent: Monday, September 05, 2011 6:20 AM
              To: atlas_craftsman@yahoogroups.com
              Subject: Re: [atlas_craftsman] Grinding BIts

              HSS is not damaged by being hot. It has the property of 'red hardness",
              which means it is still hard when at some degree of red heat.

              In fact, it is difficult to anneal HSS, most ordinary cooling rates will
              harden it. There is a special cooling time/temperature profile to anneal
              it.

              it IS however, possible to damage it by quenching too fast, such as in
              water. The edge can develop small cracks, and it will then tend to
              "crumble" under cutting pressure.

              JT

              [Non-text portions of this message have been removed]

              ------------------------------------

              TO UNSUBSCRIBE FROM THE LIST:
              You do this yourself by sending a message to:
              atlas_craftsman-unsubscribe@yahoogroups.com

              Atlas-Craftsman Projects list is at http://groups.yahoo.com/group/atlas_craftsman_projects/

              To see or edit your personal settings, view the photos, files or links http://groups.yahoo.com/group/atlas_craftsman/

              The Atlas-Craftsman Wiki is at http://pico-systems.com/cgi-bin/Atlas-wiki/Atlas.cgi
              Please submit things you think will be useful to Jon Elson at mailto://elson@...! Groups Links




              [Non-text portions of this message have been removed]
            • Dean
              Hi dw; What JT (jerdal) said about heat and quenching is pretty much what you need to know. If you get your tool to a red heat while grinding, let it cool by
              Message 6 of 17 , Sep 5, 2011
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                Hi dw;
                What JT (jerdal) said about heat and quenching is pretty much what you need to know. If you get your tool to a red heat while grinding, let it cool by itself.

                --- In atlas_craftsman@yahoogroups.com, "dws" <dwshelf@...> wrote:
                >
                > Is this the kind of thing which can be reduced to numbers? Is there an ideal (grit,grade) for grinding HSS lathe bits? Or maybe a set of functional grit/grade pairs?
                >

                "Reduced to numbers".. kind of. A grit of about 60 works pretty well, but the hardness of the composition that holds the wheel together is just as important, and that is the part that seems to be the big unknown when choosing a wheel.

                Look for a wheel that is considered more "friable". That's what the wheel makers call the property that lets the wheel shed old dull abrasive and renew the cutting ability of the wheel as it wears.
                In AO wheels, the makers often use colors to identify friablity. The dark gray and blue wheels are usually the hardest, and don't do so well on HSS. White or pink AO wheels usually work very well for HSS. I use a light white 60 grit AO wheel made by Norton for tool bit shaping, and can go from a blank 3/8" HSS bit to ready to use general purpose cutting bit in just a few minutes. These wheels cost about twice as much as the crummy hardware store grinding wheels, and only last about half as long, but they get the job done fast and without a lot of heat buildup. (I'd rather spend my time on the lathe than on the bench grinder..)

                Note that different companies may use somewhat different color codes for their products. You will probably not go wrong in using a white or pink colored wheel for your HSS sharpening.

                Keep in mind, if you get a very coarse grit wheel, like 24, you may have to touch up your cutting tool after using that wheel to get to your basic tool shape. Very coarse grit leaves little lines on the ground surfaces of your tool, and you might have to give them a lick on a harder or finer wheel to get rid of those lines. They can affect the finish on the piece you're cutting in the lathe.

                Dean
              • Jon Elson
                ... You could put it in our links section, however! Jon
                Message 7 of 17 , Sep 5, 2011
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                  RG Sparber wrote:
                  > Richard,
                  >
                  > I'm always looking for new ways to share what I have written but I'm not sure what you are suggesting.
                  >
                  > When a new article comes out, I share them with various Yahoo groups. If the subject has nothing to do with lathes for example, I do not tend to share them with atlas_craftsman. Often, but not always, I will update an article and announce the change. It depends on what has changed.
                  >
                  You could put it in our links section, however!

                  Jon
                • jerdal@sbcglobal.net
                  The coloration varies more than the code does. there is an industry code, and in the code is a letter for grade , or friability. a book example from an old
                  Message 8 of 17 , Sep 5, 2011
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                    The coloration varies more than the code does. there is an industry code,
                    and in the code is a letter for "grade", or friability.

                    a book example from an old Norton brochure.................32A46-H8VG

                    first is type the 32 is a norton number code for style/type
                    A is for aluminum oxide
                    46 is the grit size
                    H is the "grade" or hardness. A is soft, Z very hard
                    8 is a "structure number" designating details of the bond material 0 is
                    dense, 12 open
                    V is a "vitrified" bond
                    G is a Norton code

                    Carborundum Corp recommend an "O" grade and 36 grit for roughing lathe
                    tools, an "L" grade and 60 grit for finish grinding. Both with a "6"
                    structure

                    JT

                    ----- Original Message -----
                    From: "Dean" <deanw@...>
                    To: <atlas_craftsman@yahoogroups.com>
                    Sent: Monday, September 05, 2011 10:17 PM
                    Subject: [atlas_craftsman] Re: Grinding BIts


                    > Note that different companies may use somewhat different color codes for
                    > their products. You will probably not go wrong in using a white or pink
                    > colored wheel for your HSS sharpening.
                    >
                    > Keep in mind, if you get a very coarse grit wheel, like 24, you may have
                    > to touch up your cutting tool after using that wheel to get to your basic
                    > tool shape. Very coarse grit leaves little lines on the ground surfaces
                    > of your tool, and you might have to give them a lick on a harder or finer
                    > wheel to get rid of those lines. They can affect the finish on the piece
                    > you're cutting in the lathe.
                    >
                    > Dean
                  • jerdal@sbcglobal.net
                    yep..... it is only when you get the edge stinkin hot that you run into problems, and that is unlikely holding by hand. In fact, holding by hand is
                    Message 9 of 17 , Sep 5, 2011
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                      yep..... it is only when you get the edge "stinkin hot" that you run into
                      problems, and that is unlikely holding by hand.

                      In fact, holding by hand is recommended as a way of AVOIDING such problems.
                      You can't hold a cutter the end of which is too hot, not unless you are made
                      of sterner stuff than most of us.... And even then your calluses are likely
                      to be smoking.

                      JT


                      ----- Original Message -----
                      From: "RG Sparber" <rgsparber@...>
                      To: <atlas_craftsman@yahoogroups.com>
                      Sent: Monday, September 05, 2011 9:06 AM
                      Subject: RE: [atlas_craftsman] Grinding BIts


                      > JT,
                      >
                      > I guess I get away with a water dunk because I grind until it is
                      > uncomfortable to hold. I've never had an edge crumble on me.
                    • RG Sparber
                      Jon, You ve got it. Rick ... From: atlas_craftsman@yahoogroups.com [mailto:atlas_craftsman@yahoogroups.com] On Behalf Of Jon Elson Sent: Monday, September 05,
                      Message 10 of 17 , Sep 6, 2011
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                        Jon,

                        You've got it.

                        Rick

                        -----Original Message-----
                        From: atlas_craftsman@yahoogroups.com [mailto:atlas_craftsman@yahoogroups.com] On Behalf Of Jon Elson
                        Sent: Monday, September 05, 2011 8:43 PM
                        To: atlas_craftsman@yahoogroups.com
                        Subject: Re: [atlas_craftsman] Super Articles...

                        You could put it in our links section, however!

                        Jon
                      • Richard Marchi
                        I ve done a lot of grinding of HSS bits. Using an inexpensive hard wheel can result in nice work IF you really pay attention to keeping the wheel well
                        Message 11 of 17 , Sep 6, 2011
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                          I've done a lot of grinding of HSS bits. Using an inexpensive "hard" wheel can result in nice work IF you really pay attention to keeping the wheel well dressed and sharp. I use the star dresser frequently in that kind of wheel. The fact that HSS CAN take a lot of heat doesn't mean that you need to heat it excessively. Using a sharp wheel of 40 - 60 grit I can rough out a 3/8" HSS bit in a couple of minutes, never heating the bit beyond light straw and cooling it frequently in water. The radius can either be stoned, as Rick suggests, or ground freehand if you want a larger radius. If you can afford the better, friable wheels, go for it! They are much easier to keep sharp and keep the bit cooler for a proportionally heavier cut. Just don't believe that you can't get a great grind on the less expensive, harder wheels. I like to finish with a 120 grit, then stone lightly with a Norton India slip.

                          good luck!



                          Dick Marchi

                          Gangplank Marina
                          Washington, DC 20024




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