MACHINING METHOD BY DRILL

PROBLEM TO BE SOLVED: To bore a work and machine an inside diameter part and an outside diameter part by using one drill. SOLUTION: In an ordinary boring work, a work W is machined by the end edges of two throwaway tips 2 and 3 at the end of a drill 1. When an inside diameter part is machined, one throwaway tip 2 is attached so that its edge 2a protrudes outside a shank 1a. The drill 1 is moved in X-axis and Z-axis directions. The cutter edge 2a is positioned in an inside diameter part Wa so that it is turned toward the minus direction on the X-axis within an X-Z plane and the work W is rotated so that the inside diameter part Wa is machined by the cutter edge 2a. When an outside diameter part is machined, the drill 1 is moved in the plus direction on the X-axis, the cutter edge 2a of the tip 2 is positioned in an outside diameter part Wb so that the cutter edge 2a of the tip 2 is turned toward the minus direction on the X-axis within the X-Z plane and the work W is rotated to machine the outside diameter part Wb by the cutter edge 2a.