I tell a lie, first pass of the thread runs at 2mm pitch, second pass runs at 0.95 pitch, it's not until the third pass does the thread pitch revert to the programmed pitch of 1.411mm.
Have checked all my settings, spindle index led works on the Diags page so Mach should pick this up, also turned off spindle speed averaging.
Anyhow, I've added two lines of code to my G32 thread, two air cuts then do the thread. This seems to work on G32 but I think G76 will be a no no.
I'm starting to look kindly at SmoothStepper, pity the exchange rate is bad.
jim.