Ah, the "Cheap servo's"
Get an encoder on them. I used the E2 from USdigital. These servo's have a nominal terminal voltage of 36VDC. Get or build a power supply that is 36VDC @20-25 amps.
Get 4 Gecko G320's
Place these into a metal box with a fan blowing on the Gecko's
Get or make a LPT breakout board. Connect the proper pins from the 25 pin LPT connector to the Gecko's (check your controller software for proper pins)
Connect the servo motors leads to the Gecko's
Connect the encoder to the Gecko's
Get +5VDC to the Gecko's (From PC or external wall wart)
In a nut shell, there you are.
Thanks
Jeff Davis (HomeCNC)
http://www.homecnc.info
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)