Okay here's the rub;

Recently installed a new bearing on a trapezoidal screw after which was able to true everything up just nicely and reassemble went wonderful. Recalibrating is turning in to a nightmare. at 1/8 step I can get it to move wonderfully but to calibrate it to steps per distance it goes nuts and drops steps and over rev's. I am using a Motion King 23HS8603 NEMA23 motor, a DIYCNC PCPPS-3 BOB and DRV25PS drivers with a 24V 14.6A PSU on a 500mm by 250mm by 50mm Gantry router. It wants to set at 514 steps per unit on the Mach3 control I am using via a pure serial (no USB involved).

If I set it at 250 for step up testing it will run out from the motor fine and back. When I start trying to run it at the setting that comes up from testing which is slightly above 514. It will start dropping steps and over reving. This is setting the acceleration as low as it will for the steps per unit. the speed is at either 1000mm/min or 1500mm/min and same results.

So the question is do I need to upgrade the motor or slow down the speed? As this is slowing a few important projects down. Thanks for any and all useful responses.

Michael