On Wed, 28 Jan 2009 15:22:09 -0500, SteveA
wrote:

On Wed, 28 Jan 2009 10:12:05 -0500, "Chet"
wrote:

I've been toying with the idea of experimenting with some basic CNC...
The motors that are offered are rated according to oz/inches of power.
How do you develop a sense for the size you would need?
For example, just how much is 131 in/ozs of torque????
Is there a way to translate that number into some demonstrable amount?
Clamp a torque wrench into a vice and turn?
Thanks for any possible practical insight...
Chet

What you ususally care about is axis thrust, and that depends on the
ballscrew pitch and any pulley ratios between the motor and ballscrew.

Axis thrust = motor torque*2*pi/(distance traveled per motor rev)

Of course, efficiency and friction will reduce this, but it will get
you in the balpark.

HTH,
STeveA

Steppers have problems with large inertial loads that are rigidly
coupled.