I made a 2X4 & caster dolly for my TSC carryall and it works great but I struggled coming up with a 2X4 design for my First Choice tiller. There is not many flat areas on the bottom of a tiller! /forums/images/graemlins/confused.gif
For the tiller, I bought two pieces of ¼ X 3 inch channel (about 16 inches long) and put heavy-duty casters on the ends of each channel. I slide the channel over the depth runners on the tiller and insert a 3/8 inch pin through the channel to secure it to the runner. The pin goes through the channel, on top of the runner so that it can’t fall off. It works very well.
John