The Blue Spot Tools External Chamfer/Deburring Tool (3-19mm) is used to clean and repair the thread of a damaged threads and studs between 3-19mm. The blades are manufactured from Tungsten Carbide which is extremely hard wearing and has a very high melting point (2, 600°) making it ideal for cleaning threads & studs. For use on stainless steel, hardened steel, mild steel, copper, brass, fibreglass, hard plastic and more. Ideal for use with electric drills.