benny, I wanted to do exactly that, but didn't end up because I couldn't figure out how to connect a bike to the mill.
At any rate, if you do end up motorizing it (as I have) give Luke at
Aus Pulley Co. in windsor a call.
No affiliation etc etc, but I went through 4 power transmission specialists before I got onto that guy, and they all f*cked me around royally, and had no clue what they were talking about.
I eventually got the suggestion to call APC. I rang them up, and it turns out they make all their own pulleys. They only normally do imperial sizes, but they happened to be casting alu pulleys in the size I needed the next day, so he put one aside and bored/keyed it 12mm x 4mm for the millmaster.
Turns out he's actually made a bunch of pulleys in this weid size for some homebrew shop in the blue mountains, I can only assume theyre also for a millmaster
Anyway, I've just build my table (worst carpentry ever) and it goes like a weapon.
Another note while I'm talking about motorizing - I've read about people mounting the motor to a board on hinges connected to the mill table, and just using the weight of the motor to give the belt enough tension. I tried that, but my hinges flexed too much, so I just bolted it to the table in the right spot. I can get the belt on/off easily but there's still plenty enough tension in the belt - enough to start without slipping with a hopper full of wheat anyway, which I think is probably the worst case situation.
phew.. sorry bout the long post, but hopefully it helps anyone thinking about motorizing.