How close should I expect to get when calibrating the x and y axises on a Lead 1010 machine? I used a 24 inch machinest rule, placed it against the shank of an upside down bit (held in the router) then taped the rule in place and set this point to 0,0,0. Next I moved the machine 23.900 inches and measured end of rule to bit using a depth micrometer. The machine had moved to 23.924. Off by .024 inches in 24 inches. Should I expect the machine to do better than this?
Yes, you should get better than that. Have you followed the calibration procedure? A longer ruler would also help to get it even more accurate.
Finish the calibration first. Theoretical resolution is 200 deg per rotation motors * 1/8th microstepping = 1600 microsteps per rotation. Leadscrew is 8mm pitch per rotation. 8mm / 1600 microsteps = 0.005mm per step practically it will be a bit more (part tolerances, leadscrews are rolled, etc) but that's what the calibration wizard is for, correcting for those tolerances in your actual as-built
...also make sure you have as little backlash as possible in the X and Y axes {well, Z as well of course). At the end of the day, a machine is only as accurate as the care taken while building it.
When I send mine 1000mm, it goes 1000mm. But I calibrated it at that length to be as accurate as possible. Also a V bit right above the ruler at 0 seems easier.