Hopefully these two videos will work one is the how to load and fire the cannon the other is a fun video of what its like to be a cannon ball.
Step 14: Wheel Making
This is a finished wheel I made it a 5" diameter. I wanted a bumpy shape so I traced a 5" circle and used a hand jig saw to cut them out. I would now suggest just using a 5" hole saw. The hole in the center of the wheel is 5/8".