Two-stage broaching of engine block bearings

摘要

A method and apparatus for broaching a series of axially aligned and spaced bores in which a first broach is provided for broaching in an initial operation. The first broach has circumferentially extending cutting teeth. The first broach also has arcuately spaced, longitudinally extending grooves which cross the cutting teeth and divide the cutting teeth into arcuate segments. Broach guides in the spaces between bores have ribs arranged in the same arcuately spaced relation as the grooves about an axis coinciding with the aligned axes of the bores. The first broach is advanced through the bores with the ribs slidably received in the grooves to guide the first broach and the cutting segments, broaching arcuately spaced sectors of the bores but leaving unbroached ridges therebetween. A second broach broaches the ridges left by the first broach.