If you want a neat little cheap controller unit try "
SharpSky focus controller". He also have
a newer unit with dew control as well.
Can buy it built or build yourself, has manual step control and full ASCOM control.
I gave up on a adapting a diy stepper motor and used a ML stepper on my ML focuser, mainly because it has a clutch system. But some folk hve buit very nice stepper motor systems using the sharpsky controller.