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Taper thread and finishing adjustment

M Code

Apr 4, 2021

I don't have experience in taper thread. However, our shop may have API reg thread in the future I want to collect information to start prepare that.

in the normal thread, I am using G92 cycle with roughing and finishing, in finishing I will use X value offset in wear to keep extra stock for 1st article and use a ring gauge for finishing adjustment.

in the taper thread from the programming side it's clear to me I will use G92 cycle with R-value based on taper angle etc..

but from the process and finishing adjustment and process inspection for API reg

1- Do I use X value only for finishing adjusment or Z & X both?
2- I can't use ring gauge in this kind of thread since there is a seal area, so what is the reference in finishing adjustment .. is it the pitch diamtere beased on gauge point?



Sep 25, 2010
1. Use X only. Z will have the effect of shifting the threading helix.
2. Thread is normally measured based on pitch diameter only.

Try using G76.