OK latest update...

Been trying to mill a 3D rooster from the Cut 3D demo program this afternoon and found a problem with my machine, after doing a finishing cut with a 3mm ballnose it returned to x0 y0 and was about 3-5mm out. I put it down to loosing steps and tried different settings in the motor tuning by changing the velocity and accel, made absolutely no difference at all.

Then I remebered that I had upped the kernal speed when trying 1/16th stepping so I dropped it down from 45k back to 25k and hey presto, no more lost steps, in fact the motors are running a lot smoother and the ballscrews vibration seems to have dissapeared.

Don't fully understand this so if someone could explain why the kernel speed was so critical I would be interested to know.

I am ruuning mach on an old compaq P3 866mhz machine but in the driver setup program it said it was running 'excellent' at 45k.