We bought a "low cost" CMM a few years ago. It cost $10,000, which is very, very little as CMMs go. I insisted on the "high accuracy model", supposedly good for +/-.010".
You know what? After you power the machine up and calibrate it, it ... just sits there and does nothing. You have to touch the probe to points of interest and press a button once for each point. Which doesn't sound very taxing, but you have to touch _exactly_ the right points to get meaningful data about a regular feature like a circular boss, and you have to touch a _lot_ of points to capture an arbitrary surface. The worst part is trying to digitize an edge, or any male feature, by touching along it with a pointed male probe... which keeps slipping off. WHile at the same time supporting the floppy arm and moving the probe in such a way that you don't bang into a travel stop or disturb the workpiece location. Speaking of which, if you get the workpiece in the wrong part of the arm's envelope, you can't touch all the parts in one setup... and good luck correlating data from two sessions with the arm and part in different relative positions.
Using a CMM is tedious, mind- numbing work, that no one will do for more than an hour without protesting or finding something else to do or demanding a raise.
You'd be better off to buy a nice surface plate, height gage, angle gages, gage pins, etc.,, and do your measurements in more traditional ways, and you'd still have some beer money left over.
Mike Halloran
Pembroke Pines, FL, USA