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Thread necromancy needed - locking a dial

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  • Thread necromancy needed - locking a dial

    Some time ago, a few years perhaps, someone posted a diagram of a mechanism to lock a dial. The dial rotates freely on a hub. A screw runs through the center of a hand wheel, along the axis of rotation. The end of this screw is a wedge, and this contacts a rod mounted in the hub that travels radially to the hand wheel's axis of rotation. When the screw is tightened, the rod is forced outward, where it contacts the underside of the dial, locking it into place with friction.

    Anyone remember that diagram?

  • #2
    Subscribing, I want new big dials too.
    Andy

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    • #3
      I did show the parts from the Rivett.....

      1601

      Keep eye on ball.
      Hashim Khan

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      • #4
        I thought it was you, I did not remember it was the Rivett. Thanks sir!

        Not even a spring. Cool.

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        • #5
          wait a minute ...

          I thought thread necromancy ... was like talking to dead threads
          John Titor, when are you.

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          • #6
            So your handwheel must have a set screw? My atlas uses a stud and nut at the end to keep the handwheel on but that can be changed for something cool like this! I knew I subscribed for a reason! Thanks for the pic!
            Andy

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            • #7
              My Atlas' 1" diameter dials have a slot set screw. So to use them I have to keep a tiny slot screwdriver handy, and a loupe, too. In short, it isn't happening.

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              • #8
                I replaced the screws on mine with ones that have a nylon tip, provides a controllable amount of friction.

                Edit: Oops, that was on the shaper, the lathe dials are mounted in a way that discourages that solution.
                Last edited by Optics Curmudgeon; 01-13-2013, 08:34 PM.

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                • #9
                  Originally posted by Tony Ennis View Post
                  My Atlas' 1" diameter dials have a slot set screw. So to use them I have to keep a tiny slot screwdriver handy, and a loupe, too. In short, it isn't happening.
                  You can contrive to put larger dials on that, you know, and it can then include a reasonable settable zero. It fixes both those problems.
                  .
                  "People will occasionally stumble over the truth, but most of the time they will pick themselves up and carry on" : Winston Churchill

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                  • #10
                    Hence the reason for this thread.

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                    • #11
                      Originally posted by Tony Ennis View Post
                      My Atlas' 1" diameter dials have a slot set screw. So to use them I have to keep a tiny slot screwdriver handy, and a loupe, too.
                      My 10" Rockwell needs the slotted screwdriver too, but I can pass on the loupe - my dials are about 1 1/2" in dia. and my eyes are still somewhat OK.

                      edit: but the Rivett meathod, I like!
                      Last edited by Scottike; 01-13-2013, 09:41 PM.
                      I cut it twice, and it's still too short!
                      Scott

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                      • #12
                        Got a couple of machines here that just have on 'O' ring installed on one of the parts, some have it inside the dial, some on the shaft retained part.
                        Dial stays where it is by friction but still resettable when needed.

                        Seems a very elegant and simple system to me.
                        .

                        Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.



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                        • #13
                          I am not a fan of the slotted screw locks on dials. Or any other kind of screw. But it does allow you to set the position of the dial without disturbing the position of the screw.

                          So, how well does the locking screw in the shaft work in this respect? I mean, you are turning the lock screw in the threaded hole in the (screw) shaft so wouldn't that action tend to turn that screw shaft? And hence, disturbing the position that you are trying to set the dial to. Or does this not happen in reality?

                          I like the o-ring/friction idea that Sir John posted. You can hold the screw still while setting the dial. I did some design work in this direction some time ago with dials that had other special features. Perhaps I should return to that project.
                          Paul A.
                          SE Texas

                          Make it fit.
                          You can't win and there is a penalty for trying!

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