Originally Posted by
Sparky_NY
I converted my own series 1 manual machine recently, all 3 axis (4 actually, did the rotary table too). I made all my own brackets etc. and used nema 34 steppers. The X and Y are super simple, just a flat 1/2" aluminum plate with some slotted bolt holes for the motor and table attachments. I used 2:1 timing belt drive. I made the timing pulleys on the 4th axis.
For the Z I used a pretty simple aluminum bracket assembly. The main plate mounts up against the factory bosses at each end of the downfeed adjustment screw. Those flat bosses are the first surface machined on the head and used as a reference by the factory as the quill bore and other features are machined so they are a proper locating surface for a Z drive. I drilled/tapped those flats for the 2 mounting bolts that mounts the entire Z assembly. The ballscew is vertical with a standard ball bearing on the top and a thrust bearing on the bottom. The ballnut mounts to a steel "arm" that is drilled through and attaches to the quill using the 3/8-24 existing hole in the quill that mounts the round depth stop ring. The quill drive "arm" has a radius cut at the quill attachment end that matches the quill radius.
On my first try, I used the round hole in the stock quill depth stop ring to drive the quill. Bad idea, the dowel pin flexed and gave lots of backlash. The arm with radius matching the quill solved all the problems.
Oh yea, I used a 425oz Nema23 stepper for the quill because I had it onhand. It drives the ballscrew with a 3:1 ratio timing belt drive. I have the quill set a 80 IPM and honestly do no know how much faster it will go because 80 is plenty fast for me right now.
My whole cnc conversion cost $1500 or less and that is including $700 for a Rockford ballscrew kit for the table. I am flat out amazed how much they get in the market for motor mounting brackets and such considering how simple they are.