I have an 8mm pitch ballscrew driven by a servomotor. I need to my router through plywood, what sort of step down ratio would I need from my motor to my ballscrew? My motors are around 600oz-in
1) Measure your motor's no-load speed.
2) Multiply it by 0.8
3) Calculate your screw RPM at the axis maximum design speed.
4) Divde the results of (2) by the results of (3)
The result of (4) will be the ideal motor to screw reduction ratio.