Whilst [Frank] mentions that this assembly has a weight and torque advantage over a NEMA 17 sized stepper motor, but we see no hard data on accuracy and repeatability which would be important for ...

Modifying a stepper motor by drilling a hole ... which include disassembling the NEMA-17 stepper and drilling out the shaft to pass the coil wire. [Russ] also spent some time reversing the rotor ...