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Pololu Universal Aluminum Mounting Hub, M3 Holes (2-Pack) – 4mm Shaft

by Pololu

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

The set includes two hubs, two M3 set screws for securing the hubs to motor shafts, and one 1.5 mm Allen wrench for use with the set screws. Each hub has four threaded mounting holes for M3 screws (not included).

These universal mounting hubs are designed to work with most diameter shafts, including round shafts and “D” shafts. Each of the two included hubs has four mounting holes for M3 screws (not included), letting you mount custom wheels or mechanisms to your motors. The two included M3 hex set screws (one for each hub) allow secure coupling of shaft to hub, and a 1.5 mm hex wrench is included for use with the set screws.


Dimensional Drawing 3mm 4mm 5mm 6mm 8mm
Diameter 17.5mm 19mm 19mm 25.4mm 25.4mm
Thickness 5mm 5mm 5mm 9.2mm 9.2mm
Weight1 2.8g 3.2g 3.2g 6.8g 6.7g
Mounting Hole Size2 M3 M3 M3 M3 M3

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