From-scratch build for wheel steering (hardware)

[abarrow]

Hummm. For engaging/disengaging, and if you are using geared pulleys, You could make the wheel pulley in two concentric parts, the geared part on the outside and a fitting smooth part inside it. Then slot the inner part so that you can put a screw handle that will expand or contract it, so when expanded it would lock to the outer gear pulley.

Hard to describe in words, but I don't think it would be that complex to make.