Re: [CAD_CAM_EDM_DRO] where's the torque ?

R Rogers wrote:

>turbulatordude <dave_mucha@...> wrote:
>I've been running thru the torque numbers for motors and seem to be
>missing something.
>
>A 1-1/2hp treadmill motor with 5,100 RPM has 296 oz-in torque.
>
>On a rack and pinion. and using a 1.25" pitch, we can round the
>distance per gear rotation to 4 inches. 1.25*pi=3.926, so 4 is close
>enough.
>
>When we calculate for a leadscrew, we come back to inches of table
>movement. do we also do that for routers ?
>
>I mean that we put on a 600oz-in motor, then multiply that by 5TPI to
>get 3,000 OZ-IN that would mean 3,000 per inch, no ?
>

No. You get an effective moment arm of .0318" with a 5 TPI screw. (That's
the radius of a circle with a circumference of .200", the lead of a 5
TPI screw.)
So, 600 Oz-In / 0.0318 = 18,868 Ounces = 1179 Lbs of linear force.

With a stepper, this is at near zero speed, however. Actual force
available, assuming
a ballscrew, might be less than 500 Lbs, but that is still quite a lot
of infeed force.

Jon