4 model

Free

2mm diameter circular shaft (female) to Lego Mindstorms "x" shaft (male) adapter

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Free

Stepper Motor NEMA17 Shaft Coupler 5.0mm Diameter

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Free

42 mm diameter shaft for Multiple Mechanism Auto-Rewind Spool Holder

Thingiverse

Free

Grippy Knob for 5mm Diameter stepper motor shaft

Thingiverse