[rholliday]

I am converting a Sharp manual mill to CNC 48" x travel and 16" y
What is the advantage of a belt drive over a direct drive?
If you use a belt drive what is the best pulley ratio?
I have a 1160 in/oz Keling KL34H2120-42-8A Stepper and G201 Geco Drive
and will be using Mach3

[Crevice Reamer]

Hi rholliday. Welcome to the Zone!

First, I assume that you are talking about connecting stepper to lead screw either directly or with timing pulleys and belt--NOT about Belt drive system of driving router axes--Which is a whole 'nother thing.

SERVO motors have good torque into high rpms and need to be geared down to produce real work. Servo motors are usually geared with timing belts and pulleys.

STEPPER motors have max torque at rest and lose it as they increase in speed. Gearing with pulleys is often a wash, because motor must run faster thereby losing torque to screw.

That's a large stepper motor and large motors tend to run slower than smaller motors anyway.

I recommend direct drive, or if pulleys ARE used, then 1 to 1 ratio.

Wire the motor Bipolar Parallel and power it with 72-80V PSU for best results.

CR.

[rholliday]

CR thanks for the reply.
I just ordered the RULAND couplings for the X drive.
I will do the X drive first then the y and later the Z
Still looking for ball screws. the backlash on the X is .020 and .014.