Skyline, I understand your point. Earlier in the conversation, it sounded like the suggestion was just to put a DC motor on instead of a stepper, as though one could just slap any old DC motor in place. This is where I hope the DC motor in question is actually a servo motor! But let me be the first to say, I may have misunderstood the intent of that earlier post.
I agree completely, The "motor" in question would need to be either one of the newer "self correcting" steppers with an internal position sensor and feedback loop to correct for missed steps or a true servo motor with a built in driver that could accept the same control signals (Step/Direction I assume). Both are pretty expensive components due to their complexity.
The cheaper and most often adopted solution (even in some quite large and expensive machines) is good old fashioned open loop steppers provided they can develop sufficient torque to overcome the likely resistance.
I have found the steppers on my machines are able to produce torques quite out of proportion to their tiny size and modest cost and rarely if ever "lose steps"
(and they are getting both smaller and more powerful all the time)
In a fault condition where for example an axis inadvertently hits a solid object that it shouldn't, open loop steppers actually have a slight advantage, they will lose steps until the controller "thinks" they are at their final position and then stop.
In the case of a servo, due to the feedback the controller "Knows" that it is not in it's final position and may continue to drive the motor in an attempt to get there.
This is a generalization of course and not always true. In reality overload protection should protect both the motor and to a lesser extent the machine. (whatever it may be).
So the choice is up to the individual both open and closed loop will work but for this particular application, I personally would stick with plain stepper motors.
Best Regards Mark