Sorry Gerry dont know what you mean by "drives"
Motors are Keling stepper motors with 8 wires and wired as unipolar
The 3 drives for the 3 motors are Probotix http://www.probotix.com/stepper_motor_drivers/ProboStep/
I have set the steps on the drives to half step and in mach (steps per) to 4000
Hope that is what you want
Nicolas
Couple things. Is the current pot set correctly on the drives to match the motors?
And What voltage are you running at?
Do the motors sound "smooth", or do they sometimes sound rough at certain rpms?
I'm in the process of setting up my router using a Xylotex drive, and on my Z axis, with 1/2-10 acme, I'm currently getting 50ipm with an accel of 7. You should be able to set your accel much higher than 2.
If the motors sometimes sound rough, you could be seeing resonance. I made a damper for my Y axis, and increased velocity from 80 to 180 with a huge increase in smoothness, and accel set at 12. Although this is with 1/2-8 2 start acme.
I'm guessing you don't have the current adjusted right, possible. Also, try running in 1/8 step mode and see if it'll let you go faster, as microsteps allow the motor to run smoother.