The X-weight cloth backing of our 3M™ Cross Pad 341D supports both grinding and polishing applications. It has a closed coat of aluminum oxide abrasive secured with a heat-resistant resin bond. This cross pad works well where close-tolerance polishing or deburring is needed. A cross pad attaches to a threaded mandrel (sold separately) that attaches to a rotary tool such as a die grinder or drill. Together, the mandrel and cross pad enable the user to grind or finish the inner contours of various-sized channels. Max RPM depends on the size of the pad. Aluminum oxide is a popular choice among industrial professionals because of its fast cut-rate and long life. This mineral makes a tough, durable abrasive that self-fractures to expose fresh cutting edges, whereas traditional natural abrasives dull more quickly. Due to its fast cut-rate, hardness, and strength, it is widely used in grinding applications in addition to sanding and finishing applications. Aluminum oxide is suitable for a wide variety of materials in both woodworking and metalworking, including ferrous alloys. Resin adheres the abrasive particles to the cloth backing, creating a strong, stiff bond that withstands the high heat and pressure of heavy sanding.