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Holding threaded parts in the lathe

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  • Holding threaded parts in the lathe

    Here's a tip that may be well known to regulars, but I used it the other day to solve the problem of holding a 6-32 shcs in the 4-jaw chuck so I could drill a longitudinal hole through it. I don't have a collet set. I screwed it tightly into a solid round die, and then centered the die with a dial test indicator. It worked well enough, but it would have been better to center the screw itself, laying a thin shim against the threads.

  • #2
    Good tip. I have also used several wraps of masking tape on occasion for fine threads but you must be careful to finish an even number of wraps with no wrinkles. Another thing that works reasonably well is to run a nut partway down a threaded bolt then clamp it and the bolt head in the 3 jaw chuck.

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    • #3
      I'll wait for the jokes...

      Similar to HWooldridge's post, I have a few Al nuts with a kerf sawn, the 3 jaw chuck "squeezes" the nuts tight against the threaded parts.
      Today I will gladly share my experience and advice, for there no sweeter words than "I told you so."

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      • #4
        Never thought about using a die, good tip Herb.

        I use Techshop's method, bore the bushing to about .001 undersize
        saw it three ways for a 3 jaw and guess how many for a 4 jaw
        I also use a small positioning collar on it to face up against the jaws.

        When precise positioning is not needed, HWooldridge clamping the nut method is really quick.

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        • #5
          I usually take a small piece of scrap round stock, chuck it in the lathe, drill and thread a hole, then screw my work piece in that hole. I use the tailstock to ensure that the tap is propertly aligned with the hole.

          Once I get my machine shop set up, I am going to make up a set of these holders so I don't have to make one when I need it.

          Regards,

          Rif
          There are only 10 types of people in the world: Those who understand binary and those who don't.

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          • #6
            Near the end to be worked run two nuts onto the thread and lock them together. Run a third nut on the other end and align its flats with those of the aft nut in the locked pair. Close the 3-jaw on the lands of these nuts with the forward nut outside the jaws. The locked pair hols against rotation and the third nut provides alignment. Its easy and it works
            John R

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            • #7
              Really not a machinist

              Wonder if you could use the right sized Heli-coil? they are a little bigger but a three jaw would make them evenly compress.

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              • #8
                A Helicoil is very hard. I think it would damage the chuck jaws.

                What I have used is brass tubing in a size to slip over the threads. I cut off a piece the length of the threads and then cut a longitudinal slit.

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                • #9
                  I use brass tubing as well. You can get telescoping tubing at most hardware stores in sizes from 1/8" OD to over 5/8" OD with a .014" wall. a quick slit along the length and you've got a thread protector/indicating surface (although don't expect .0001" accuracy as the latter).

                  Stuart
                  Stuart de Haro

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