Reach 3D Foot for 20mm extrusion

This is a foot designed for the Reach 3D printer, with a little retro style thrown in. The Reach 3D printer uses 20mm extrusions for construction, and this foot is designed to fit that extrusion type, so it should be useful for other projects as well.

This is designed to attach with one t-nut, but also includes a robust nub to fit in the extrusion.