Pololu Universal Aluminum Mounting Hub for 3mm Shaft, #4-40 Holes (2-Pack)

by Pololu

These universal aluminum mounting hubs allow you to mount custom wheels and mechanisms to 3mm diameter motor shafts.

The set includes two hubs, two #4-40 set screws for securing the hubs to motor shafts, and one 0.05β€³ Allen wrench for use with the set

These universal mounting hubs are designed to work with most 3mm diameter shafts, including round shafts, β€œD” shafts, and Tamiya’s 3mm hexagonal shafts. Each of the two included hubs has four mounting holes for #4-40 screws (not included), letting you mount custom wheels or mechanisms to your motors. The two included #4-40 hex set screws (one for each hub) allow secure coupling of shaft to hub, and a 0.05β€³ hex wrench (often the smallest size in SAE Allen wrench sets) is included for use with the set screws.


  • Size: 17.5 mm diameter Γ— 5 mm thick
  • Weight: 2.8 g1
  • Shaft diameter: 3 mm
  • Mounting hole size: #4-402

1For a single hub only (without set screw).
2This is also the size of the set screw.