Extra Long Wood Drill Bit is a rod-shaped or helical tool with cutting edge at the end, which is used to process through holes or blind holes. The difference between woodworking drill and woodworking end mill is that there is no cutting edge on the side. Besides the main cutting edge, the wood drill has a sharp countersunk cutting edge on the outer edge to cut off wood fibers and make the side of the hole smoother.
There are many kinds of special tools for processing tenon holes, such as hollow square chisel, hollow square chisel with drill bit, chain drilling knife and machine chisel, etc. The end face of the hollow square chisel has a crescent-shaped cutting edge for cutting square corners around the drilling hole. A hollow square chisel with a drill bit is a cutting tool combined with a drill bit and a square chisel, and the drill bit is installed in the hollow square chisel. Chain drilling tool is a kind of continuous rotating chain type multi-tooth tool, which is similar to milling or longitudinal sawing when machining tenon holes. When the tenon hole is opened with a chisel, the chisel makes up-and-down reciprocating cutting motion.