the last 2 sentences I understood,   I don't understand why you would build it with a rotating table in the center.
Why not just fix your part stationary and move around it with your x & y?

Jeff,
You can use your existing driver cards (if this is the type I am thinking)  the orange and brown wire are step and direction, I forgot which is which.  Black and red are the power lines.  I converted one for the high school here back 8 years ago.  Beware of noise from the spindle DC controller board,  I had to put some small caps on the step and direction lines or every time I ran the spindle the machine would move on its own.

a lot of the breakout boards can be scaled for something less that 10v.  But I don't think it would matter,  you could make a simple voltage divider of 2 resistors of equal resistance across the output of your breakout board and tap into the center for your output to your motor controller.

Don,
Not easy to determine with the limited information,  do you have mfg & model of controller? 
I suspect it would be the common on the black wire, and 0-10v+ on the white wire, but can't be positive without more info.
If you have a multimeter measure the black to white as you cycle speed up and down, that will give you further confirmation.

Mike,

Hey thanks a lot,  I will check this out. 

Zarzul

That is the problem,  the ESC controller takes a hybrid type of PWM. 

Since I am using this for engraving and PCBs the high speed works pretty well.

Thanks for your insight, the info on poor turndown is very useful.   I wonder if these could be run from a different type of controller?  Like a DC servo motor controller with encoder like you suggested?

Has any had much luck using a PWM signal to run an ESC controller for a RC plane outrunner motor as a spindle.
I am trying to do this but having some difficulties.
The PWM is a little different for the ESC controller. 

This is a description of how they work.
DC ESCs in the broader sense are PWM controllers for electric motors. The ESC generally accepts a nominal 50 Hz PWM servo input signal whose pulse width varies from 1 ms to 2 ms. When supplied with a 1 ms width pulse at 50 Hz, the ESC responds by turning off the DC motor attached to its output. A 1.5 ms pulse-width input signal results in a 50% duty cycle output signal that drives the motor at approximately half-speed. When presented with 2.0 ms input signal, the motor runs at full speed due to the 100% duty cycle (on constantly) output.

I have had some success by doing an odd ball start sequence where I start the spindle and call for 50 rpm which gives me a 1ms pulse width, then a pause to allow the ESC to initialize, then I call for 100 rpm (scale of speed is 1000 rpm) and it will run 2ms pulse for full speed on the motor.
 

just a bump to remind of my email address change  arnie@wyomingwireless.com

Richard,

Try stretching the spring a little more.

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