Those aree weird screws.... I've never seen ballscrews with that odd pitch. As they are 13/64" lead, they need to turn 64/13 turns to move one inch. Gerry is absolutely correct that it is useless to use 40X micro-stepping. Anything more than about 10X gains you nothing of value. So, using 8X as Gerry suggests, you'd have:
200 Steps/Turn * 8 uStep/Step * 64/13 Turns/Inch = 7876.923076923 Steps/Inch
Regards,
Ray L.