Need Advice for Clone Conversion
I have a "Unimac" clone of a Bridgeport knee mill with a 42x9 table, 24x12 travel. I would like to convert it to CNC with the quill as the Z axis. It will be used mainly for prototype work, with some light production on aluminum a few hours a day.
Elrod seems to have what I would characterize as a top of the line quill conversion. They also sell ballscrews and XY conversions. In a recent email to me, Dwayne Elrod said, "I really encourage knee mill retrofitters to use 1350 Oz. In. motors..."
An alternative to Elrod's ballscrews are Rockford ball screws. They are described as precision rolled ballscrews. They are less expensive than the ones for Elrod, and also less precise. But they are certainly accurate enough for my work.
The questions:
1 - Do I really need 1350 Oz. In. motors? I was looking at the Reliance 0690 servos that are rated at 22 Lb. In. (352 Oz In) continuous. Elrod gears them up 2:1 and I would do the same. There seems to be a factor of 3 or more in cost.
2 -- Who besides Elrod has a Z axis quill conversion? Are they any good? What provisions are made on these conversions for limit and home switches?
3 -- The acme screws on my machine are 1.250-5tpi. The largest of Rockford's screws in 5 pitch seems to be 1.150 in diameter. Is that likely to be a problem?
4 -- Who besides Elrod has motor mounts/pulley kits for the X and Y axis?
5 -- My intention is to use EMC for the software (I'm a linux guru), and pico controllers. Does anyone have any comments on these choices?
Are there any other questions I should be asking? Do you have answers?
Thanks,
Ken
Kenneth Lerman
55 Main Street
Newtown, CT 06470