Glass Saw: Rigid Diamond Wire Ring Driven by Its Rim

Jesse Cogswell's ring saw (US 4,576,139, 1986) for glass, ceramics and stone. The blade is a rigid circle of wire coated with bonded diamond, standing upright through a cutting table. A rubber-tyred wheel on the motor drives it by friction round its own rim at 3000 ft/min or more, and twelve guide wheels on slots round an aluminium back-plate hold it true. Because it cuts with any part of its rim, the work can be turned freely for curves and inside shapes; a sponge in a water tray wets the wire. The patent sizes the ring from the thickest work to be cut (8 in ring for 3/16 in); the notebook does the sums. The picture: the patent's Fig. 1.