Printed this out last night. Great dimensioning, m3 nut and m3 bolt fit in the smaller gear nicely! 5mm stepper motor shaft fit nice and snug in the smaller gear as well!
Printed mine at 100% infill and experienced overheating of the extruder stepper motor consistently for the first time. Had to add cooling fan on extruder motor to ensure a successful print(heat transferred from motor through shaft to the filament driving nut, softening it and causing jams(printer issue, not model issue).
Awesome gear design, Triffid!