The Weiler 56490 mandrel securely mounts a Type 1 cutoff wheel with a 3/8" arbor hole onto a grinder that accepts 1/4" stems. The mandrel is designed to fit 0.035"- to 1/4"-thick cutoff wheels and is made of carbon steel for strength and extended tool life. The mandrel consists of a shank and a screw. The shank inserts into a grinder chuck. The arbor end of the shank accepts a cutoff wheel, and the screw portion of the mandrel threads into the shank, securing the wheel to the mandrel.