SOUNDS like you need to get someone to TUNE the servos so they run correctly.

(;-) TP

I would also like to point out that your stepper analogy is not as accurate as you think. Microstepping is not accurate, it is somewhere between the commanded microstep and the one next either way so at the very best all you can say you are +- 1 microstep and that is before you take any of the parts of the machine into equation.

If your servo system has 500 line encoders then the theoretical resolution would work out to the same as a stepper system with 10 microsteps, which would be more accurate would depend on the tuning you can achieve in your servo system. If you have higher count encoders 2000+ line count then, assuming your servo drives are capable, you will have a much better chance of having much more accuracy than you could hope for with stepper.
However as I mentioned before a Bridgeport is not a rigid machine and personally I would be happy at  +-0.0005"  accuracy.
 Hood

However as I mentioned before a Bridgeport is not a rigid machine and personally I would be happy at  +-0.0005"  accuracy.
 Hood

I too would be ecstatic.  I am afraid that I need more than just a servo tune.  Then the $500 for a servo tune and the extra $500 for new encoders and god knows what else will end up being money in the lake.  I rather have the $10,000 for teh complete package from Mach motion and call it a day with self tuning AC brushless servos, closed loop controller etc etc.