Great for Metalworking in Hard-To-Reach Areas Standard Abrasives™ Cartridge Roll Mandrels were designed to help users get inside diameters and holes to swiftly grind and finish. The mandrels enhance usability of Standard Abrasives™ Cartridge Rolls (sold separately) by being the tool attachment that links the cartridge roll to the power tool. Adding length to the cartridge roll helps it reach even further into those seemingly inaccessible nooks and crannies. The mandrel attaches to a rotary tool such as a die grinder or drill, and comes in different sizes to fit a variety of cartridge roll sizes. Tips for Optimal Use For safety, Standard Abrasives recommends that the mandrel pilot length used to drive a cartridge roll should measure at least 1/2 inch less than the overall length of the cartridge roll. If a cartridge roll measures 2 inches in overall length, for example, the corresponding mandrel should have a pilot length of no less than 1-1/2 inches. The versatile range of diameter sizes of Standard Abrasives™ Cartridge Roll Mandrels enables operators to select the right mandrel for their power tool and cartridge roll.The mandrel consists of a shank and a pilot. The shank end fits into the tool chuck or collet while the pilot end fits into the arbor hole on the cartridge roll. The mandrel was conveniently designed to fit all shapes of abrasive cartridge rolls, including straight, full tapered, half tapered, sidewall. It is made with plated steel for added durability. It may be used with a die grinder or random orbital sander. ​