coil winder/unwinder

i have some old marklin ho scale trains that have different coils in them. to repair those locos i made this coil winder. on the end of the 10mm shaft you can slide different fitment pieces to fit different coils etc. you can unwind broken coils by hand and rewind them using the motor. its made with an generic motor with a diameter of 21mm 10mm steel rod and 6200 bearings. i choose the ones without seals to lessen friction.