Need a little experiment carried out....

[Jonathan]

Basically I was hoping that applying dc to one coil of a stepper it would act as a brake. the lathe clearly has much more grunt so no braking effect was seen

The stepper motor is definitely applying a torque opposing the lathe and if I just hold the motor it feels like that torque is a function of the phase current - presumably they're proportional. The torque ripple is high though since we're operating it as a single phase motor.

i wonder if turning it by hand would empirically show the braking effect and maybe measure the effect using pulley and falling weight approach

I think measuring the torque using the method I suggested earlier would be easier?