The Forney 60122-1/4-Inch Ball Shaped Tungsten Carbide Burr is shank mounted tungsten carbide burrs are double cut for fine work. Designed for use on ferrous metals, plastic, fiberglass and other machinable materials. Great for deburring, sculpting and removing material in hard to reach areas. Designed for use with high speed die grinders and electric drills. Forney Industries is one of America's longest operating family-owned metal working product companies. Founded in 1932, Forney offers more than 5,000 products for the hardware, automotive, farm and ranch and do-it-yourself markets. 1/4-Inch (6.35 mm) ball shaped tungsten carbide burr (SD-1). 70,000 Max RPM. Proof of purchase required. neglect, negligence or accident, or that has been used in any way contrary to the purpose intended.