Hey guys

Ok,

direct drive motors, so no gear reduction.

1.8 degree motors = 200 steps per rev.

10x microstepping = 2000 steps per rev.

8tpi 2 start screws (4tpi effective) = 8000 steps per rev.

This is the part I'm not sure of.

I want to run metric programs and DRO's, so divide 8000 by 25.4 ?

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I set steps per in the mach motor screen to 314.96

EDIT: I also thought maybe it was the rounding, and set it to 314.96062 with the same result.

When I run from zero, to 700 mm, the measurement I get is approximately 1mm farther than it should be.

Am I missing something here?

Thanks

EDIT2:

Swiped from another post, but modified to fit my numbers:

4 TPI = 1/4 = 0.25 inch pitch 0.25 x 25.4 = 6.35mm pitch

so

200 steps per rev x 10 micro steps = 2000 steps per rev

1 rev = 6.35mm so 2000/6.35 = 314.96062 steps per mm.

It would appear my way of calculating it came up right too?