PURPOSE: To decrease the area for installing a device by installing an index device which can set selectively, on a movable rail, the first machining head allowing machining of a portion to be machined without reciprocating motions and the second machining head allowing machining of a portion to be machined with reciprocating motions.
CONSTITUTION: After holding a crank shaft on a work holding device 2, the first machining head 71 selected previously on a movable rail 8a is moved forward together with the movable rail 8a and the crank shaft is rotated without the effect of reciprocating motions of the holding device 2 and then super- finishing is made by the first machining head 71. Next, the movable rail 8a is moved back, an index device 9 is actuated to select the second machining head 72 on the movable rail 8a and said head is moved forward together with the movable rail 8a, and at the same time, the holding device 2 is made to exhibit its reciprocating motions, the crank shaft is rotated with reciprocating motions in its axial direction and thus super-finishing by the second machining head 72 is accomplished.
NAKAJIMA KATSUYUKI
TAKASAKI KIMISANE
