[clfrye]

Does anyone know what the steps per mm setting should be under the motor tuning section of Mach 3 for Sherline 3700 rotary connected to a 200 degree stepper motor?

[Bell 430]

200 degree stepper? do you mean a 1.8 stepper? I don't have the sherline table, but I have a larger one I have converted to CNC. I use 435 Steps per DEGREE with a speed of 300.

[awerby]

Bell's right - for a rotary axis, the unit is a degree, not a millimeter. The Sherline rotary table is geared 72-1. So it takes 72 revolutions of the motor to rotate through 360 degrees, or 5 revolutions per degree. Since your motor has 200 steps per revolution, the number of steps required is 1000. But if you're using a micro-stepping driver, you'd need to multiply that by the microstepping factor - if that's 10 microsteps per step, then your number is 10,000. If you're using a half-stepping driver, then it's 2,000.

Andrew Werby
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