I'm pretty sure I have the same machine you are describing. I've done alot of modifications to the machine which I think are invaluable to the usability of it. The first mod was to get rid of the original steppers as you mentioned. I went with Step Syn 1.8 degree, 3.0a steppers that I got off of ebay for a great price. I don't really remember exactly what I paid, but it was less than $150 for all three. I'm not really sure of the torque of the motors either ( the number on the motor is: RM26A3D) but they are more than enough for the mill and I have never lost another step after the conversion. The motors are driven by a Nudrive 4 axis controller bought off of ebay for $500. The motors are 6 wire bipolar steppers and I think have 180 ozin of torque. They are very similar to these motors on ebay: item number 120413334314. And it just so happens that there is a nudrive controler on ebay right now too, auction number :290304446179. This combo has proven itself for the last 4 years cutting mostly aluminum. I also upgraded the spindle with a sherline 10k rpm unit that cost me another $500. Obviously I have spent a little more than your projected budget of $400, but It has been very much worth it in the long run for me. I've made countless "things" on the machine, and after 4 years its still going strong but showing some signs of wear and tear. My normal cuts are in the 26 ipm range and a very conservative .020 doc. But on some occasions (operater error) the doc was increased to a very lively .125 or more with no lost steps or other issues other than the spindle not holding up to the increased cutting pressures.  |