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Set Screw to Avoid Shaft Damage Question

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  • bob_ledoux
    I m completing an index plate that screws to a collar. The assembly mounts on the drive end of a Taig lathe headstock. I plan on using three set screws to
    Message 1 of 9 , Feb 6, 2009
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      I'm completing an index plate that screws to a collar. The assembly
      mounts on the drive end of a Taig lathe headstock. I plan on using
      three set screws to mount the plate to the headstock to ensure no
      slippage during use.

      I'd like to have a "soft" set screw to avoid scarring up the shaft.
      I've considered placing a bit of lead on a steel set screw tip. I've
      also considered making set screws from brass.

      Are there other bright ideas?
    • greg.mcfadden@gmail.com
      there are set screws with nylon or plastic tips, as well as brass and silver. check out mcmaster.com -Greg ... [Non-text portions of this message have been
      Message 2 of 9 , Feb 6, 2009
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        there are set screws with nylon or plastic tips, as well as brass and
        silver.

        check out mcmaster.com

        -Greg

        On Fri, Feb 6, 2009 at 10:28 AM, bob_ledoux <bobledoux@...> wrote:

        > I'm completing an index plate that screws to a collar. The assembly
        > mounts on the drive end of a Taig lathe headstock. I plan on using
        > three set screws to mount the plate to the headstock to ensure no
        > slippage during use.
        >
        > I'd like to have a "soft" set screw to avoid scarring up the shaft.
        > I've considered placing a bit of lead on a steel set screw tip. I've
        > also considered making set screws from brass.
        >
        > Are there other bright ideas?
        >
        >
        >


        [Non-text portions of this message have been removed]
      • Nicholas Carter and Felice Luftschein
        Two brass tipped screws at 90/120 degrees on the collar will likely hold well enough. Alternatively you can file flats on the shaft where the setscrews contact
        Message 3 of 9 , Feb 6, 2009
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          Two brass tipped screws at 90/120 degrees on the collar will likely hold
          well enough.
          Alternatively you can file flats on the shaft where the setscrews
          contact to avoid scars.
          This provides a bit more force as you can use regular screws and any
          burr will be below the shaft surface.

          bob_ledoux wrote:
          > I'm completing an index plate that screws to a collar. The assembly
          > mounts on the drive end of a Taig lathe headstock. I plan on using
          > three set screws to mount the plate to the headstock to ensure no
          > slippage during use.
          >
          > I'd like to have a "soft" set screw to avoid scarring up the shaft.
          > I've considered placing a bit of lead on a steel set screw tip. I've
          > also considered making set screws from brass.
          >
          > Are there other bright ideas?
          >
          >
          >
          > ------------------------------------
          >
          > To Post a message, send it to:
          > taigtools@yahoogroups.com
          >
          > To Unsubscribe, send a blank message to:
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          > Let the chips fly!
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          >
          >
          >
          >
          >

          --
          felice@... is Nicholas Carter and Felice Luftschein. See our
          homepage at www.cartertools.com/nfhome.html
        • Tony Jeffree
          I think you will find lead is way too soft for that. A better approach is to use a brass pad between a steel screw and the shaft. An alternative worth thinking
          Message 4 of 9 , Feb 6, 2009
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            I think you will find lead is way too soft for that. A better approach is to use a brass
            pad between a steel screw and the shaft.

            An alternative worth thinking about is to make a split collar and use a socket head screw
            to pinch the collar onto the shaft. This will give excellent grip and no marring of the
            shaft.

            Regards,
            Tony


            -----Original Message-----
            From: taigtools@yahoogroups.com [mailto:taigtools@yahoogroups.com] On Behalf Of bob_ledoux
            Sent: 06 February 2009 18:28
            To: taigtools@yahoogroups.com
            Subject: [taigtools] Set Screw to Avoid Shaft Damage Question

            I'm completing an index plate that screws to a collar. The assembly
            mounts on the drive end of a Taig lathe headstock. I plan on using
            three set screws to mount the plate to the headstock to ensure no
            slippage during use.

            I'd like to have a "soft" set screw to avoid scarring up the shaft.
            I've considered placing a bit of lead on a steel set screw tip. I've
            also considered making set screws from brass.

            Are there other bright ideas?



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

            To Post a message, send it to:
            taigtools@yahoogroups.com

            To Unsubscribe, send a blank message to:
            taigtools-unsubscribe@yahoogroups.com

            Let the chips fly!
            Yahoo! Groups Links
          • David Robertson
            You can also use split collars.. attached to the index plates on one side of the split collar. They provide a friction grip of the shaft with no set screw.
            Message 5 of 9 , Feb 6, 2009
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              You can also use split collars.. attached to the index plates on one
              side of the split collar. They provide a friction grip of the shaft
              with no set screw.

              See
              http://davesclocks.googlepages.com/usingpetersonindexplatesonataigheadstock

              David

              Nicholas Carter and Felice Luftschein wrote:
              >
              > Two brass tipped screws at 90/120 degrees on the collar will likely hold
              > well enough.
              > Alternatively you can file flats on the shaft where the setscrews
              > contact to avoid scars.
              > This provides a bit more force as you can use regular screws and any
              > burr will be below the shaft surface.
              >
              > bob_ledoux wrote:
              > > I'm completing an index plate that screws to a collar. The assembly
              > > mounts on the drive end of a Taig lathe headstock. I plan on using
              > > three set screws to mount the plate to the headstock to ensure no
              > > slippage during use.
              > >
              > > I'd like to have a "soft" set screw to avoid scarring up the shaft.
              > > I've considered placing a bit of lead on a steel set screw tip. I've
              > > also considered making set screws from brass.
              > >
              > > Are there other bright ideas?
              > >
              > >
              > >
              > > ------------------------------------
              > >
              > > To Post a message, send it to:
              > > taigtools@yahoogroups.com <mailto:taigtools%40yahoogroups.com>
              > >
              > > To Unsubscribe, send a blank message to:
              > > taigtools-unsubscribe@yahoogroups.com
              > <mailto:taigtools-unsubscribe%40yahoogroups.com>
              > >
              > > Let the chips fly!
              > > Yahoo! Groups Links
              > >
              > >
              > >
              > >
              > >
              >
              > --
              > felice@... <mailto:felice%40casco.net> is Nicholas Carter and
              > Felice Luftschein. See our
              > homepage at www.cartertools.com/nfhome.html
              >
              >


              [Non-text portions of this message have been removed]
            • bob_ledoux
              Hi, Nick, I looked at two types of collars. One was in two pieces with two bolts that tighten the halves together. The other was a single piece with one bolt
              Message 6 of 9 , Feb 6, 2009
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                Hi, Nick,

                I looked at two types of collars. One was in two pieces with two
                bolts that tighten the halves together. The other was a single piece
                with one bolt that provides clamp action.

                I wanted multiple screws between the collar and the index plate to
                ensure a true and solid joint. Any flexibility in the collar makes
                that difficult.

                So I chose to make a slip fit assembly where the collar was solidly
                mounted to the index plate.

                My experience is that flats can't be counted on providing a secure
                mount. My headstock pulley set screw rests on a flat and the small
                set screw in the pulley does not prevent some radial slippage of the
                pulley.

                My sense is multiple soft press points, on a round shaft surface,
                provide a more secure mount.

                On an index plate there is no room for any slip.

                --- In taigtools@yahoogroups.com, Nicholas Carter and Felice
                Luftschein <felice@...> wrote:
                >
                > Two brass tipped screws at 90/120 degrees on the collar will likely
                hold
                > well enough.
                > Alternatively you can file flats on the shaft where the setscrews
                > contact to avoid scars.
                > This provides a bit more force as you can use regular screws and any
                > burr will be below the shaft surface.
                >
              • Will Schmit
                If it has an index plate, might it be a good idea to add a key? ________________________________ From: bob_ledoux To:
                Message 7 of 9 , Feb 6, 2009
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                  If it has an index plate, might it be a good idea to add a key?




                  ________________________________
                  From: bob_ledoux <bobledoux@...>
                  To: taigtools@yahoogroups.com
                  Sent: Friday, February 6, 2009 12:59:38 PM
                  Subject: [taigtools] Re: Set Screw to Avoid Shaft Damage Question


                  Hi, Nick,

                  I looked at two types of collars. One was in two pieces with two
                  bolts that tighten the halves together. The other was a single piece
                  with one bolt that provides clamp action.

                  I wanted multiple screws between the collar and the index plate to
                  ensure a true and solid joint. Any flexibility in the collar makes
                  that difficult.

                  So I chose to make a slip fit assembly where the collar was solidly
                  mounted to the index plate.

                  My experience is that flats can't be counted on providing a secure
                  mount. My headstock pulley set screw rests on a flat and the small
                  set screw in the pulley does not prevent some radial slippage of the
                  pulley.

                  My sense is multiple soft press points, on a round shaft surface,
                  provide a more secure mount.

                  On an index plate there is no room for any slip.

                  --- In taigtools@yahoogrou ps.com, Nicholas Carter and Felice
                  Luftschein <felice@...> wrote:
                  >
                  > Two brass tipped screws at 90/120 degrees on the collar will likely
                  hold
                  > well enough.
                  > Alternatively you can file flats on the shaft where the setscrews
                  > contact to avoid scars.
                  > This provides a bit more force as you can use regular screws and any
                  > burr will be below the shaft surface.
                  >




                  [Non-text portions of this message have been removed]
                • Clive Foster
                  Lead is indeed too soft to go under a standard W point set screw. It squishes. A little copper pad is probably best. Allegedly the top work hardens under the
                  Message 8 of 9 , Feb 6, 2009
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                    Lead is indeed too soft to go under a standard W point set screw. It
                    squishes.
                    A little copper pad is probably best.
                    Allegedly the top work hardens under the W point so it stays tight
                    and doesn't squish out but the shaft side stays soft giving good
                    grip. Can't say I've noticed but copper has always worked for me.

                    General rule on getting stable grip between bore and shaft with set
                    screws is to arrange two points and a line or two lines and a point
                    contact. Line contact is needed to stop things rocking along a line
                    pretty much parallel to the length of the shaft.

                    So three equal spaced screws are bad. Three points let it rock.

                    Two screws at 90 to 120 degrees angular spacing push the bore over
                    against the shaft opposite the mid point between the screws to get a
                    line contact.

                    Drilling a hole parallel to where the bore will go with its centre on
                    the circumference of the bore before boring will give you two lines.
                    A single screw opposite will hold fine. Hole diameter around 1/4 of
                    bore size or a bit under is about right e.g. 1/8 hole with 13.7 mm
                    bore is common for pin mounts as used in optical experiments. They
                    hold very accurately.

                    Round hole is impractical for large shafts but a flat in the bore or
                    on the shaft works OK. Flat has to extend right through the bore.
                    Hence if you have a a full bore length flat on the shaft the screw
                    should go opposite the flat which is very counter-intuitive. If you
                    want to use a W point direct on the shaft put a short flat where the
                    screw will bite.

                    Exception is if you have a flat key. Here the screw goes on top of
                    the key. Figuring why out from scratch will give you a headache. I
                    think I know the reasoning but I'm darned if I can explain it
                    comprehensibly.

                    Lastly if you have plain pointed set screws remove them from packet
                    or flange and deposit in the scrap bin. The primary purpose of those
                    things is to muck up shafts and make you swear. Any period of
                    apparently effective holding is an inadvertent by-product. If you
                    must use a plain point provide a suitable conical hole so contact is
                    on the side of the point and take off the sharp point, about 1/4 of
                    the cone length will do, before installing.

                    Clive
                  • Clif Lowry
                    Just grind a flat on the shaft, then marring won t become a problem. Clif San Antonio _____ From: taigtools@yahoogroups.com [mailto:taigtools@yahoogroups.com]
                    Message 9 of 9 , Feb 6, 2009
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                      Just grind a flat on the shaft, then marring won't become a problem.



                      Clif

                      San Antonio



                      _____

                      From: taigtools@yahoogroups.com [mailto:taigtools@yahoogroups.com] On Behalf
                      Of bob_ledoux
                      Sent: Friday, February 06, 2009 12:28 PM
                      To: taigtools@yahoogroups.com
                      Subject: [taigtools] Set Screw to Avoid Shaft Damage Question



                      I'm completing an index plate that screws to a collar. The assembly
                      mounts on the drive end of a Taig lathe headstock. I plan on using
                      three set screws to mount the plate to the headstock to ensure no
                      slippage during use.

                      I'd like to have a "soft" set screw to avoid scarring up the shaft.
                      I've considered placing a bit of lead on a steel set screw tip. I've
                      also considered making set screws from brass.

                      Are there other bright ideas?





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