Hi Jonathan..

This may be straying into the realm of the theoretical, not sure such a thing as a hollow lead screw exists.. But I do see your point although the inner mass of a solid would still require movement and account for some of the power required to rotate it.. Just checked florins posted specs and he has used 25mm dia leadscrews, and 2 nema 34 12N motors to power them.. Those motors would probably pull my car up a hill..!

Steve..