PURPOSE: To increase the polishing times of a punch, by providing the reciprocating position of the punch so as to move in the direction approaching to a die with a projection length adjustable screw.

CONSTITUTION: Levers 22 and 24 are rocked when an eccentric cam 11 is rotated, and a punch 14 guided by a guide 32 is reciprocated in the right and left direction. And, a contact 1 and fraction 4 are cut off from the hoop material which advances by being guided by a guide groove 33, when the right end cutting edge part of the punch 14 is crossed with a die 15, the contact 1 falls straight down and also the fraction 4 becomes sliding down from the slope of the die 15. The punch 14 repolishes the cutting edge part torestore the sharpness in the case of the sharpness of the cutting edge being reduced. And, the projection quantity of a screw 28 is enlarged, when the punch 14 becomes short and not crossed with the die 15, the screw 28 makes the upper part of the lver 24 so as to project more than the past in the right direction. Then, the punch 14 is moved in the right direction together with a roller 17 and fitting 29 and the crossing with the die 15 becomes possible.