Self-restrained got wood to solve former broach to discharge bits with broach not free, calorific and serious, manufacturing efficiency is low problem. Attached drawing is when the packing wooden case of maker bed, need to just go up in board and thick wood often bore. We use the bit of fried dough twist that machines a metal all the time previously, but it discharges bits not free, calorific and serious, manufacturing efficiency is low, and when drilling a few especially deep hole, broach length is insufficient. For this, we convert self-restrained 45 steel broach (like attached drawing) , the result is favorable. Is the method that make: ? The staff that urges car of?5 date steel to become Ød, heat with acetylene blaze next one hair is red, hit its with the head flat, put into oil to quench instantly, go up in emery wheel finally wear the pointed horn of 60 ° , grind a point in pointed horn both sides. CNC MillingCNC Machining