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View Full Version : Lathe thread a #12-40 thread, or just buy the die?



Paul F
09-10-2005, 04:51 PM
I'm faced with having to cut some #12-40 NS adjustment screws... maybe 10 of them... about 1" long each.

I'm puzzling over how to work-hold and adequately and accurately cut the thread in my lathe... my 8" 3-jaw or 10" 4-jaw seem like overkill!

I'm wondering if I should try it, or just break down and buy the die for #12-40NS.

Any other advice on threading or turning small diameters is appreciated too! (And I DO plan on building a 5c collet nose for my lathe...).

Thanks in advance!

rockrat
09-10-2005, 06:59 PM
I had to cut a thread like that for a peep sight on a muzzleloader. I was going to chase the threads on my lathe, but I had to order something from J&L anyway so I bought a tap and die in 12-40 instead.

http://www.jlindustrial.com/catalog/product.jsp?origin=SEARCH%3AKEYWORD&id=DSP-73250L

$10.48 for the die.
rock-

sch
09-10-2005, 08:26 PM
Square block 5c collet holder in the 4J is a cheap interim measure and has uses in indexing on the mill and could be centered to any desired accuracy. Sold in kits with a hex holder for $20-30.
Steve