Screw Mandrel For Buffing Wheels. This is a new 1/4" (6 mm) screw mandrel. This is for use with buffing wheels. Has a 1/4" (6 mm) shank. We work hard to update our descriptions and pictures of our merchandise. As part of a process of ongoing innovation by our suppliers, newer versions of the item shown may be shipped before we are able to complete an update. As a result there may be a slight variation in color and design.