Despite having some misgivings, I bought an Ebay bargain, 20 mm diameter, 20 mm lead ,nsk ground ball screw and nut and then afterwards saw the caveat against coarse pitch screws on the "ball screw basics" thread here. I guess I don't understand why it won't work well -the screws are very accurate, and can't one simply set driver for high microstep (maybe 1/10) and get plenty fine resolution? Or is the coarse pitch incapable of sustaining much of a load? Still, it would have to be far better than the Dumpster CNC antibacklash nuts many use? I'm planning on using this afor a 25" long Y axis for a moving table on a fixed gantry woodworking CNC router. I don't need high speed -50 inches/minute would be fine, but it will be doing inlay work, so high accuracy is required -- by woodworking standards anyway -maybe .002-.004 combined backlash/repeatablity. Here's my screw; http://cgi.ebay.com/ws/eBayISAPI.dll...m=260235880436.