you are using a disc made for use in a table or radial arm saw. I have two made by Sears (craftsman) that work very well. They are made of a very very heavy steel plate- heavier than the blade by about double. I agree with the previous poster - they are extremely versatile since you can tilt them, use the rip fence, or the miter guage- and - you have a choice of two grits on each disc.

I make replacement paper discs with floor sander paper and contact cement.