[holygrail]

We used a 1/2 inch coupler from Grainger and lathed the other end of the shaft down to 1/4 inch for an encoder. The set screws work fine, but I wish we had a continuous shaft from the gearbox or a hex axle instead. We used a different motor and gearbox than you though. It was a banebots 775 with a 4:1 gearbox and it has worked pretty well.