Hello Bill - seeing you are watching the topic.

The drivers cards for the motors control how many pulses they put out to the motors, to move one step of the rotation. On my cards you can switch between 1,2,4 and 8. That moves your motor 1 step. If you have 1.8 degree motors, then you need 200 of these to turn the spindle 1 revolution.

Mach3 then needs to know how many pulses you need to move 1 inch (or 1mm). So you start at your step rate multiplied by your motor angle multiplied by any gearing multiplied by your leadscrew. e.g. mine is 1/8 step, 1.8 degree motors, 3 to 1 gearing and a 1/10inch leadscrew, so Mach3 needs to put out 8 x 200 x 3 x 10 i.e. 48,000 pulses per inch.

If I have to put out 4.8 pulses per 1/1000th of an inch it is certainly accurate.

Jim Pinder