A shank with a screw-like head. Used primarily with Dremel polishing bits and accessories. For best results, insert the mandrel all the way into the tool and then back it out slightly before tightening down. This provides plenty of shank for the collect or chuck to hold onto. Simply remove the screw, line up a cut-off wheel or sanding band over the hole in the shank and replace and tighten the screw. Used primarily with Dremel polishing bits and accessories1/8 in. shankUse with cutting wheels, sanding discs, and polishing wheelsUsed primarily with Dremel polishing bits and accessories.The 402 mandrel is used primarily with cut off wheels but is used with the following Dremel accessories 409, 411, 412, 413, 420, 423, 425, 426, 456, 511, 512, 540 and 541.