Dynabrade Pencil Grinders are an ideal tool for use in casting houses, effective on cast parts of aluminum, bronze and brass. Quickly and efficiently removes gates and parting lines in cast parts. NEW Quick-Change Lever. Turn lever outward 90º to open collet insert and easily replace accessory. These grinders accept variety of accessories: carbide burrs and mounted points are sold separately. Quick-Change Lever; Turn lever outward 90 degrees to open collet insert and easily replace accessory.Unique housing shape allows tool to be held as a traditional Die Grinder.