For those of you trying to make your own DIY 3D milling machine, take a look here, a great resourceful site for that.
The CNC project also included the design and construction of three independent forced air cooled twenty six volt five ampere power supplies, Three MOSFET’s based unipolar chopper drive circuits, A Digital high speed ISA bus interface, several Analog to Digital and Digital to Analog boards, Time base circuitry, and all of the associated wiring and circuit board construction as well as milling machine time required to fabricate all of the parts. System metrics afford resolution to .0005″ with infinite repeatability and accuracy of plus or minus .003″ through the use of low back lash ball nuts and 5/8 hardened cold rolled linear ball screw. Horizontal linear motion is facilitated by the use of eight Thompsons super pillow block linear bearings
