Pololu Universal Aluminium Mounting Hub for 3mm Shafts – #4-40 Holes (2-Pack)

We have an assortment of universal mounting hubs available, spanning several shaft sizes and featuring mounting holes threaded for metric or imperial screws. These universal mounting hubs are designed to work with most 3 mm diameter shafts, including round shafts, “D” shafts, and Tamiya’s 3 mm 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 0.05″ hex wrench (often the smallest size in SAE Allen wrench sets) is included for use with the set screws.

These hubs will work with any mini/15.5D metal gearmotor or micro metal gearmotor, and they also work with 60mm, 70mm, 80mm, and 90mm Pololu wheels (excluding the Multi-Hub versions; see the individual wheel pages for compatibility details).

Specifications

• Size: 17.5 mm diameter × 5 mm thick
• Weight: 2.8g*
• Shaft diameter: 3 mm
• Mounting hole size: #4-40**

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