Unable to cut correct thread with G76

Patrik T wrote: It is a stepper so it is possible I am losing steps, but why would I only lose steps when using G76.

I was wondering if, perhaps, trying to synch to the spindle is causing more-than-usual accceleration.

Out of interest, what is your acceleration setting for the Z-axis (and the max velocity).

The thing is that for most people threading works perfectly, so I am wondering what is different about your setup.

Yeah, that was what we concluded the last time we discussed this, that the fast variations of my light weight spindle meant the z-axis acceleration can not keep up. I accept that that is the cause of my problem. Therefore I expect to not have the same problem on the lathe I am building now. Still, the same acceleration settings work with the other algorithm.

So, to cadcam, I kind of resolved the issue by accepting the cause to be as described above.