[Clive S]

On the Drill/Tap tab. Using MM. Say I want to tap M8x1.25. I enter the 1.25 in the pitch box and the threads/mm box, auto puts in 0.8 (the box is marked threads/mm).

Q. I think this is showing 0.8 inches should it not show 1.25 as that is the thread per mm. The program dose in fact tap the thread correctly.

[dannirr]

Pitch is the distance between threads, not the number of threads per mm. So the number of threads per mm is 1/pitch = 1/1.25 = 0.8

[Clive S]

Pitch is the distance between threads, not the number of threads per mm. So the number of threads per mm is 1/pitch = 1/1.25 = 0.8

Yes you are quite correct, I don't know what I was thinking. Brain fade. Thanks