Hi Lee
"Has anyone or do anyone run a Treadmill Motor on their machines.
from what I have read , these motors have good ajustable speed/power control with no loss of torque,
Are they easily converted for say powering a milling machine?"
Short answer YES
Lathe, Mill, Hacksaw, 2 Drill Presses all on DC motors using KB Electronics, Minarik, and Dart Controllers
That use 230 volts AC converted to 180 volts DC.
You need to know and understand how to wire them up and set them up to match the motor power.
Mistakes can be FATAL and permanent DEATH can be the consequences.
They can give excellent speed and torque control at high speeds say over 1/2 the motor RPM this falls off the available torque at low speeds.
A separate cooling fan ex computer 12 volt DC is desirable when using less than full motor speed.
I use an AMP Meter wired in on the DC motor leads For setting up and measuring the load when machining.
As for the reversing If the brushes on the motor are at 90 degrees to the commutator then no problem with running in clock or anti-clock as with a lathe or mill almost all running will be in one direction.
Download the manual from KB Electronics and or Minarik
http://www.kbelectronics.com/Variable_Speed_DC_Drives.html
Or
http://store.minarik.com/product/drives/minarik-drives/MM23001C
Hope this helps
Eric