Sure you don't have the tools? I made some out of 1/2" plywood using a
drill (press or hand) and a band (or saber) saw. That's it. Used the
chuck to mark the disk for drilling and countersinking, used a cheap
protractor and compass to mark out the holes to drill, then after all
drilling was done, cut the disk in quarters and screwed it to the
chuck. Used rubber bumpers from the hardware store. Works great!