I've got my A-Axis up and running just fine.  Now I want to do some grinding using my milling head and rotating stock in my A-Axis.  I need a way to turn on my Axis and rotate it like a spindle.  Then I want use my other three axis to drive a grinding wheel. 

Is there a way to just spin the a Axis? 

NOT and use the spindle at the same time. The option would be to drive the A axis from an outside driver and turn it on/off through an ouput pin.

(;-) TP

Wow, Thanks for the Quick response. 

My spindle is belt driven and I'm not using Mach3 to control it.  Is there a way I could make two configurations, one for normal a axis use and another for setting up my A-Axis as a spindle?

If so, how do I go about setting up a stepper as a spindle? 

Thanks in Advance. 

Matt

OK IF you are not using the spindle function in mach then set up the spindle as you would if you were using the A axis as the spindle .

Then when you need to run A as a spindle use the Swappaxis() funtion to swap the spindle function over to the A axis. Then the A axis will run as the spindle. When you are done use the Unswappaxis() to return things to normal.

Lookup the correct useage of the SwappAxis() funtions.

(;-) TP

Thanks, I'll give it a shot

Or just set up a new profile with the A axis as a spindle.

Yep that is what I dediced to do.

I tried that earilier.  My current configuration, I have the A-Axis set up at 35 steps per unit (deg).  I can set the feedrate up to 3000 and send the A to 720 and it will fly. 

When I set it up as a spindle, I bump the step up to 12,600 (35 * 360) or one revolution per unit.   I give it a S1500 M3 and it creeps.  Any ideas what I'm doing wrong?

What Velocity do you have for the spindle setup, also what pulley speed do you have for Max and are you on the right pulley?
Hood

stepper as a spindle

I would guess that the max you will get out of a stepper will be like 1000 rpm ( maybe less but you'll find out ) and no torque so yo will need some ratio increase to increase the rpm.
Additionaly if you try to control it you may find out that the stepper speed will not be linear ie; rpm increase is not linear as you increase the speed due to
torque falling off and the influence of increased torque required  to turn the spindle it's driving.
Just something you should be aware of.
RICH

set the spindle up exactly like you had the Axis and see what you get(;-)

(;-) TP