Modifying a stepper motor by drilling a hole down its shaft ... That’s what [Russ] did to make needed improvements to his CNC flat-coil winder, which uses a modified delta-style 3D-printer ...

Anyone who has ever wound a toroidal coil ... winding ring rotates on a C-shaped fixture that brackets the toroid, which itself rotates under stepper motor control on a trio of rollers. An Arduino ...