Stepper rotor/shaft re-mounting?

[uli12us]

Thats not correct, you can hold a BLDC or Synchronservo with 2 different tensions between 2 fases in an angle that is somewhere between that you have with only one of the coils with tension.

With steppers you have full torque only at very low speed, and the speed is all but smooth.
With those speeds you cant really work, today with good tools you need a feedrate of more than 60ipm. Rapid feeds of 2500ipm are not seldom, no stepper can move so fast, at least, if you want a
resolution of 0,04thou, like in many industrial machines.

[Rufe0]

Thats not correct, you can hold a BLDC or Synchronservo with 2 different tensions between 2 fases in an angle that is somewhere between that you have with only one of the coils with tension.

Which is exactly what I said...

With steppers you have full torque only at very low speed, and the speed is all but smooth.
With those speeds you cant really work, today with good tools you need a feedrate of more than 60ipm. Rapid feeds of 2500ipm are not seldom, no stepper can move so fast, at least, if you want a
resolution of 0,04thou, like in many industrial machines.

That is the whole point of a many phase stepper, it would be improved in all the areas you mentioned.

[Neale]

I don't know the answer to this one, which is why I am asking. Rufe0 says that servos with encoders need to microstep to achieve high positional resolution. I assumed that the reason for things like 2500 line encoders was to achieve (approximately) the same level of resolution as, say, 12 cascaded 200-step steppers with rather less rotational inertia. Do servo systems microstep? I've never worked with servos so have no experience of how they and their drivers are set up. I do assume that there will be a small amount of rotational uncertainty as the servo hunts between two adjacent encoder lines, but I can't believe that this is any worse than the rotational uncertainty of a stepper under varying load as it only generates a restoring torque when displaced by some (very small) distance from the exact "step" position.