The Pololu universal aluminum mounting hub allows you to mount custom wheels and mechanisms to 3 mm motor shafts. The hubs are sold inpairs, and each hub includes one 4-40 set screw for securing a motor shaft to the hub.

These universal mounting hubs are designed to work with most 3mm shafts, including round shafts, “D” shafts, and Tamiya’s 3mm hexagonal shafts. Each hub has four mounting holes for 2-56 screws, letting you mount custom wheels or mechanisms to your motors. 4-40 hex set screws (one included for each hub) allow secure coupling of shaft to hub. The included set screws require a 0.05" hex wrench (often the smallest size in SAE Allen wrench sets).

The picture to the right shows a hub with one of Pololu’s mini gearmotors and a Pololu mini metal gearmotor bracket.