A professional grade tool to secure mounting to form the outside of bowls. One of the indispensable tools for woodworkers. It's designed with a strong and thin-edged thread to securely catch the wood and ensure safety. The square shank ensures a secure clamp position of the chuck, making the whole device more durable and with long life.With the Safe Lock Woodworm Screw, you can quickly and easily install small bowl blanks without extra steps or tools. Suitable for various types chucks: Super NOVA2, G3 Nova, Robert Sorby Patriot, Record Power SC3, Record Power SC4,Harbor Freight Bauer 23222A-B,Vicmarc VM100, Record RP4000.