View Full Version : Odd thread size/split die question

05-09-2006, 11:43 PM
Hi everyone,

I've got an old screw that I need to duplicate and it is an odd one. It looks like M2.7 x .60. I can find an M3 x .60 die but not the 2.7. Can you adjust split dies so they are smaller? There's a .012" difference between 3 and 2.7 and the threads are only .014" deep. Any suggestions?


05-10-2006, 12:50 AM
Hi Stuart,

Short answer... no.

Split dies are made by tapping through, then slitting. Thus the removed portion of the threads follow the original pitch line. If you simply compress the die to the point where the edges are touching, there will be a discontinuity in the threads equal to the pitch through the kerf.

Adjustable dies are only intended to change the class of fit, i.e. perhaps .001 to .002 inch maximum.

Are you sure it's a metric thread? Your measurements are awfully close to a standard #4-40.

J Tiers
05-10-2006, 12:56 AM
You can often cheat if you have to, but that's a lot of cheating.

If you really needed to, you might be able to get close if the die were bigger, but any die for that size is small, and likely won't compress much.

But, if you really need to make the thing, and you can't just single-point it on the lathe, then you could always see if you can get there.... might cost you a die.

What's right, and what you gotta do sometimes are not the same. It can be the difference between success and failure....