BROACH FOR WORKING HOLES IN CAST ARTICLES Russian patent published in 1998 - IPC

FIELD: foundry. SUBSTANCE: broach has lower shoe with receptacle for receiving casting, upper shoe carrying sectioned punch with sections spring-loaded with plastic rod positioned within punch. Peripheral surface of broach has concentric teeth with cutting edges directed upward and terminating lower row of teeth with cutting edges directed downward. Broach is driven by press. When broach moves downward in closed state, lower row of teeth machine roughness at casting hole base. Remaining rows of teeth overlap with their cutting edges rough portion on remaining surface of hole and during movement of broach upper part cut off rough portions. Method allows roughness such as bosses having height of several millimeters on inner surface of castings to be eliminated. EFFECT: increased efficiency by high-quality removal of rough portions, difficult for access by normally used tools. 2 cl, 3 dwg