Hi,
I am retrofitting a Harrison trainer lathe to Mach4 using Pokeys57cnc and stepper drives.
It is working now and I am very happy with Mach4' turn cycles wizards!
This way it is easier to program; it is faster than doing it on manual lathe, even 1 piece-project!

But.. when threading the pitch differs from what it should be.
When asking for pitch 1.5mm it is just a little off, when typing 1.475 instead 1.5 it is a nice fit for 1.5 after machining..

I searched a lot on the web but in this case I cannot find a parameter/faulty entry where to adjust it.

I checked/facts/tried:
-When moving the Zaxis 1mm, machine is moving 1mm (0.01mm precice)
-The encoder is connected to spindle using the same toothed belt sprockets. Encoder is 1024 PPR with 1 index pulse. Wired with EMC protected wire.
-The spindle speed is 430 rev/min, the screen reads around 440, fluctuating not more than 1 or two. No speed frequency module (yet) just relays start and stop.
-I tried to tell the machine the speed is 440 in Gcode but it makes no difference.,
-I tried lower rev but did not change pitch (anyway: the max speed of Zaxis is 700mm/min, 430*1.5=645mm/min so it should be ok..)
-I checked G99 is used (feed/rev)
-check box use threading is checked at Pokeys driver and encoder settings.

The question is where to find the solution; Pokeys or Mach4?

Thanks for any suggestions!!