Originally Posted by robhrzic  Thanks for the input klxrcr and Dennis Storzek.
Hey klxrcr, yea it's looking more and more like I'm going to have to fabricate my own ball screw assembly. I just need to figure out what type of screw I need to get (ie rolled, precision rolled, or precision ground).
I also don't know whether I need to be looking at a single preloaded ballnut, or a double preloaded ballnut. Any ideas or pointers?
Though I am sure that the ground ball screw would be more efficient, relatively speaking, and allow for higher ipm speeds. Is this correct, or am I totally missing something? |
A rolled ball screw should be plenty accurate for your machine, a rolled/precision rolled will not have as accurate of a lead as a ground, but can be mapped to nearly equal precision. A single or double preload nut will work, a single preloaded nut has 2 seperate "races" in it that preload against each other, where as a double would be 2 unpreloaded nuts back to back that preload against each other.
Ground screws are slightly more efficient but a rolled screw still has a 90% efficient force transmission which is a ton better than an acme. A rolled screw will not limit the feed rate of your mill, unless you plan on 1000ipm rapids. Which I hope your not. also a rolled screw will have a bit more noise than a ground screw, just the sound of the balls spinning around inside the nut.
One last bit I priced a set of screws from elrod, precision ground for a 9x42 bridgport, $1750...... I'm looking for a cheaper set now (rolled) And I hear that Rockford has sets starting around $700.