[Jon.N.CNC]

Try the original code with backlash comp turned off.

Also, make sure you close and restart UCCNC after making any changes.

Just tried it on the i7/uc400 machine, opened and closed. No avail. jerking the same. So there we go, I think you would need a machine capable of instant acceleration to run that code without jerking.

Happy i now know ' you have to use smoothing for cutting arcs in hsm'

Interesting though the higher the smoothing value the more small straight moves it generates over arcs so the jerking starts to creep back in. 0.03 seems to be the fastest setting with the least amount of transitions between arcs and xy moves. Still get a deceleration/acceleration at each transition though. Angle is a continuous curve so wouldnt meet the cv stop angle. So still something that doesnt make sense here.

Smoothest setting for linear error seems to also be 0.03, 0.1 or 0.01 it runs at a less constant velocity. Coincidence or could it be that the linear error needs to match the cam smoothing setting.