Rail Grinder Stone for Railway Silicone carbide grinding stones in a 2" or 3" inch size wheel (flat) for grinding mild steel, soft metals, such as copper, bronze, gold, silver, etc. and some gemstones. If you need a heavy duty grinding wheel or stone to use on your polishing motor, look no further these are some of the toughest grinding wheel available. The rating on these wheels is not to exceed 8500 RPM. Fast Material Removal with Consistent Surface Finish: High speed grinding stones provide rapid material removal with excellent flatness and surface finish. This can often allow for reduced processing in subsequent steps. Suitable for Many Materials: Available with Alumina or Silicon Carbide abrasives for grinding of many different material types. PRODUCT SPECIFICATIONS Type Rail Grinder Stone for Railway Dimension 150 x 55 x 70