Image taken by Dick Watson and shown here with his permission.

The rods are M4 threaded rods and the wheels are secured by nuts.

Dick had to manufacture two extra plates to complete this mechanism.

The gears have a module of 1mm. The hole spacing is 1.5 mm.

There is quite a large selection of gears but not many pairs which mesh at the same centre distance.

The plastic plates are intended to be cut up if required.