Made with resilient rubber. Angled expansion slots through the heavy rubber rim allow the drum to expand when rotated thereby locking the finishing belt in place. Belts can be quickly changed merely by stopping the machine and slipping off the old belt and sliding on a new one. In use, the resilient drum surface flexes to fit gemstone's contour to quickly remove grinding flats, yet the convex drum concentrates the cutting action so that scratches are quickly removed even from flat surfaces. Rayspan Drums are made form a specially developed rubber compound which is soft, resilient and durable. Each drum is supplied with telescopic bushings to fit shafts ╜in., 5/8in., 3/4in. and 1in. in diameter.