Thursday, August 11, 2022

That Thumbscrew Problem

I believe that I mentioned that I solved the threading issue.  I can use the die holder that goes into the tailstock to get at least a good square start for the 10-32 thread and then finish the process with a conventional die handle.

Looking at the variety of ways to knurl the head, I believe that I found a simple way to apply straight knurling with just the mill.  I can put the screw in a chuck on a tilting table at 90 degrees.  Then use a center drill bit to cut lines 0.05" deep vertically on the head, rotate the table five degrees, and repeat.  (A CNC rotating table would simplify this and I plan to buy one this year.)  Then to add more grip, use the same approach by rotating the table continuously cutting horizontal lines every 0.1" apart.  It will not be as pretty as diamond knurling but I believe it will give enough grip.

6 comments:

  1. Before I went to all that trouble, I'd just buy a 10-32 pan head screw and run a small thumb nut up to the head, lock it, and be done with it.

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    1. It requires frequent adjusting.

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    2. I meant lock the thumb nut to the screw/head, so you can adjust the screw by turning the thumb nut.

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    3. thumb-nut: I did not know these existed.

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    4. Do thumb-nuts usually have a locking mechanism or do I use a lockwasher and nut to allow rotation both directions without unscrewing?

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    5. Not normally locking, but depending on how tight and how permanent it needs to be you can use any number of methods from a lockwasher to thread locker to epoxy or even welding.

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