The grinder is from HF $9.95 and the sanding belts are from Lowes 1"X42" $5.95 for package of three. The rest of the materials I had in the shop. The plastic is a mystery material but probably acetal. The grinder turns 11,000 rpms so I made the drive pulley the smallest diameter I could safely get away with to lower the belt speed. I drilled and taped the grinder output shaft 1/4 X 20 to attach the drive pulley. The idler pulleys are a little larger with sealed ball bearings but the size is not critical. I thought I may have problems with the belt tracking properly but that is not an issue and the geometry can be quite a bit off before there is a problem.
Thanks all
Ray
Thanks, Ray...I will surely be putting one of these together.