We decided to design and build a vex mecanum wheel prototype. It doesn’t quite work, but then again it is a just a prototype. The rollers are made of 1/4 inch tubing for the axle and 3/8 inch tubing with 5/16 inch fuel line for the wheel. The plates are made of 22-gauge steel. It mostly clears the ground except for a few spots, and all of the rollers turn freely.
Overall not too bad, but we thought we could do better…