I wouldn't be surprised to hear they hold .0005" or better in good condition. My old Sheldon will with my good 4 jaw chuck on it, but not with the 3 jaw...
How do you like your Sheldon? I picked up an EXL-56B a year or so ago, and I'm just now starting to mess around with the thing...I built a steel table for it, next project is to add a VFD. I have a rotary converter in the shop for 3ph, but I think VFD's are much better option.
