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Metric thread dial obsession (going nowhere)

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  • #16
    Here is a great thread that is on topic. Go to post number 6 to get an idea of what you need to make, and why.

    I thought about that a while, and it occurred to me that there might be a back door way to do it without a thread chasing dial. It's based on the section that said "The half nuts can be engaged every 5 revolutions of the lead screw for proper registration" and "keep the halfnuts engaged to maintain the relationship between the chuck and leadscrew rotation."

    The idea is to put a dot on the chuck, and an indicator pointing to the dot. Then position the carriage so it's beyond the start of the work. Engage the half-nuts. Mark the ways, and add an indicator pointing to that mark. Mark the leadscrew and add a pointer to that mark.

    Theoretically, when all three of the marks align you have the nuts, chuck and lead screw back in their original orientation.

    At the end of the project, there is a profound difference between spare parts and left over parts.

    Location: SF East Bay.


    • #17
      Originally posted by danlb View Post

      Theoretically, when all three of the marks align you have the nuts, chuck and lead screw back in their original orientation.

      I believe the 'old timers' used to do essentially that by chalk marking the change gears.


      • #18
        I made the comment about left hand threads in post #6, as up to that point, no mention had been made of the problems and the OP may not have thought of it.


        • #19
          Originally posted by GadgetBuilder View Post
          Does your lathe have a spindle reverse or must you add that to thread going away from the headstock?

          Now that you've got Cleeve's book you might consider a dog clutch rather than a threading dial(s).
          Ooh, I want one of those! Regardless of whether it negates the need of a threading dial or not! I think I just developed a dog-clutch obsession too
          Yes, I've got the brushless version, Sieg's SC4 which will reverse at the push of a button.

          Dan: that's a good trick with the marker. A scratch pass saved me from myself despite me thinking that only an idiot could need it. It'd be useful for testing out re-engaging half nuts and seeing whether I get a repeat or a two-start thread without waste.

          I'll look into aligning by marks. It doesn't have quite the same feel as dropping the lever on a moving part and watching it run...but if it gets the job done


          • #20
            I think danlb's suggestion in post #15 is the best possible way to familiarise yourself with threading without tears. You can repeat the exercise any number of times and not cause any damage at all.


            • #21
              Just gash a gear like cutting a wheel with a tap, free spinning on a stub and the tap in the chuck, nylon or somthing would do, mount it with a mag base to the saddle when needed, a cannibalised clock gauge makes a good visual display, you can print a clock face and glue it in place of the original scale.
              Looks like a trav-a-dial.
              Electronic leadscrew?
              Just ideas