Hi Jason,
Happy New Year!
The motorized column is just a single reversible gearmotor that switches either up or down at a reasonable rate to get the head near desired position.
After I got mine installed, I thought maybe it could have been a little faster, but I'm happy with it....something like 22 seconds to go from all the way down to all the way up. I just hold the momentary switch on until the right height is reached, tighten the spider. Then the z axis does the rest.
The motor I used was a shot in the dark from ebay. It's an Oriental Motor Co. motor 4RK25GN-AT that's tagged as 100VAC, 1250 to 1500 revs per min.
the accompanying gearhead is 4GN12.5K. (does this mean a 12:1 reduction?)
The sensor I'm using for spindle rpm was obtained from mouser... an omron part.
part no. 653-EE-SN5V. I'll have to do some reasearch to find again what size resistor I used in the circuit. It's connections are covered in liquid electrical goop, and what notes I DID take are scribbled somewhere as yet undiscovered.
John (bloy)