PURPOSE: To provide a machining method by which use of a guide bush is abolished in the machining method for a stepped hole.
CONSTITUTION: A small diameter prepared hole Hs and a large diameter prepared hole Hl having different diameters in two stages are formed in a work W, and the smallest diameter first edge part 2 on the tip of a stepped reamer 1 is brought into contact with an inlet (a) of the small diameter prepared hole Hs, and machining is started, and afterward, the largest diameter fourth edge part 5 on the base end side is brought into contact with an inlet (b) of the large diameter prepared hole Hl, and the machining is performed in a condition of supporting two points of the tip first edge part 2 and the base end side fourth edge part 5 at their opposite ends. This stepped prepared hole H is formed by a stepped drill or of a cast extracted hole.
MANABE TOSHIO
ITO MASAMI
OKAMOTO DAISUKE
