Quote Originally Posted by stirling View Post
Irving - thanks for correcting my shoddy maths - however you just model holding torque - most people want their steppers to move - in which case your maths say nothing.
On the contrary, if he's using the original leadscrews he'll need the higher low-speed torque just to get some motion. To a first approximation you get 70% of holding torque up to the corner speed. Agreed the corner speed will be higher with the lower inductance of the single coil, but that's moot if it stalls before it gets anywhere close.

But I agree, he should try it both ways, can't hurt.