Spent quite a bit more time with it tonight and I'm not exactly sure what to make of things. I had been trying to check everything out with my digital calipers. I tossed those and hooked up the magnetic slide scale I have, it's reads to .001 mm. I fixed it to the x axis itself and bolted a stop to the linear rail.
I set the steps to 409.6 and started checking things. I noticed that the X axis was off about the .4 mm I was seeing, but found out that it only happens when it's moving in the plus direction. When I move it in the minus direction it was fairly accurate but any move positive would be around .4mm off. Checking the backlash showed no serious backlash, certainly not .4 mm. I hope I"m not just being obtuse and missing something easy. I decided to try dumping .4 mm in the backlash compensator just to see what would happen and it's much better, probably around .02 - .05 mm. What would you consider good?
Thanks,
Bob