cnc stepper torque

[dragons_fire]

ive done some searching but couldn't really turn up much. does anyone know how much torque is needed for a RF30 mill/drill? i was looking at the hobbycnc kits that include steppers, and im not sure if i 305ox/in is too much or not enough. if its not enough, then i may be looking for recommendations for another setup (thats less than about $400). if its too much, then it would be great because i could go with cheaper motors.

i found one thread from Balsaman about his conversion, and somewhere in there it mentions that the motors he is using are around 100oz/in.

thanks

[Robin Hewitt]

It doesn't take much torgue to turn a handle on a ball screw (unless the Gibbs are way too tight). So you need to choose a motor that will hold it's torque at speed.

An oz-in rating for holding or pull in torque tells you very little about the motor, what you need is a graph of torque against speed.

For a stepper the graph will start of fairly horizontal then plummet, question is, is there a useable fast feed before the plummet?