calculate lead of mill / drill z axis

[Hack]

I am in the process of wrapping up my mill / drill cnc conversion and am wondering what to figure the "lead" as to enter into turbocnc. I am driving it with a stepper connected by a 1 to 1 belt and pully set up to the fine feed mechanism. What should I tell the computer the machine will move per step? This is with a G203 and 1.8 degree / step motors.

Also, I am having calculating the x and y which are belt driven 1:1 with the same steppers and controllers but with a 5/8" ball screw from McMaster carr. The lead is advertised at 13/64" so I was calculating it as:

200 * 10(microsteps of the g203) * 13/64 but obviously this is not right. What is the correct formula?

Thank you

Dan

[Torsten]

Originally Posted by Hack I am in the process of wrapping up my mill / drill cnc conversion and am wondering what to figure the "lead" as to enter into turbocnc. I am driving it with a stepper connected by a 1 to 1 belt and pully set up to the fine feed mechanism. What should I tell the computer the machine will move per step? This is with a G203 and 1.8 degree / step motors. Also, I am having calculating the x and y which are belt driven 1:1 with the same steppers and controllers but with a 5/8" ball screw from McMaster carr. The lead is advertised at 13/64" so I was calculating it as: 200 * 10(microsteps of the g203) * 13/64 but obviously this is not right. What is the correct formula? Thank you Dan

So much for truth in advertising, I believe your Ballscrews are probably .200 pitch like everyone elses they just like to spec in fractions
where 13/64 = .203 wich is close enough for a Sales clerk.
The calculation for the stepper would be
200 full steps per rev. X 10 microstep = 2000 Steps per motor revolution.
A .200 pitch screw will turn 5 times to move 1."
with a 1:1 ratio this will be 5 x 2000 = 10 000 steps per Inch
Or 1/10000 = .0001" per step resolution.
On your Z-Axes finefeed is usualy a Dial reading up to 0.1", which would make this .100" per revolution. Or 10 Revolutions per Inch.
So 10 X 2000 = 20 000 steps per Inch.
This would come out to 1/20000 = 0.00005" per step resolution.
Hope this helps, good Luck.

[Hack]

Worked like a charm, thank you for your help.

Dan