Ingocraft Wheel With Holes

The base wheels in the Ingocraft toy set have a problem: They don't connect to anything. They spin nicely -- very nicely -- around the smooth part of a long bolt, but you can't drive them with anything, and you can't translate their motion to anything else. The threaded holes in this solid wheel attempt to fix that.

This is a normal Ingocraft wheel filled in and then hollowed out with threading appropriate for Ingo bolts.