Internal pull broach with indexable inserts

An internal pull broach for working opposing walls of an aperture through a workpiece during a single stroke machining operation comprising:

• an elongated cutting tool holder engageable through said aperture of said workpiece, said tool holder having a longitudinal axis and a lateral width, a plurality of laterally extending, longitudinally spaced pockets on opposite longitudinally extending sides, each pocket extending laterally across substantially the entire width of the tool holder, said pockets divided into groups including a first pocket configuration and a second pocket configuration alternately disposed along a predetermined first longitudinal length of said tool holder;
• first and second indexable cutter insert means disposed in alternating pockets and defining a plurality of sequentially acting, longitudinally spaced protuberances, each protuberance having a plurality of linear cutting edges and indexable within said respective pocket to orientate one cutting edge at a time in an operable position providing a single, linear leading cutting edge extending laterally with respect to said longitudinal axis substantially across an entire width of said tool holder for progressively cutting into said opposing walls of said aperture extending through said workpiece sequentially as said tool holder moves during said single stroke along a fixed linear path coaxial with said longitudinal axis of said tool holder extending through said aperture of said workpiece, said indexable cutter insert means for roughing, semi-finishing and finishing said opposing walls of said aperture through said workpiece simultaneously during said single stroke machining operation to form two opposing substantially planar surfaces;
• and
• first and second fastener means for connecting said first and second indexable cutter insert means to said alternating pockets respectively, said first and second fasteners means having unique configurations such that each insert is independently indexable and replaceable within a corresponding pocket, while being interchangeable only within a respective pocket configuration group.

An internal pull broach for working a workpiece having a generally rectangular aperture extending therethrough defined by opposing walls comprising:

• an elongated cutting tool holder engageable through said aperture of said workpiece, said tool holder having a longitudinal axis and a lateral width, first and second planar faces extending along the longitudinal axis and spaced radially from one another, a plurality of laterally extending, longitudinally spaced pockets formed in each of said first and second faces, each pocket extending laterally across substantially the entire width of the tool holder;
• and
• indexable cutter insert means engageable in each of said pockets and defining a plurality of sequentially acting, longitudinally spaced protuberances, each protuberance having a plurality of linear cutting edges and indexable within said respective pocket to orientate one cutting edge at a time in an operable position providing a single, linear, leading, cutting edge extending laterally with respect to said longitudinal axis substantially across an entire width of said tool holder for progressively cutting into opposing walls of said aperture extending through said workpiece sequentially as said tool holder moves during a single stroke along a fixed linear path coaxial with said longitudinal axis of said tool holder extending through said aperture of said workpiece, said indexable cutter insert means for roughing, semi-finishing and finishing said opposing walls of said aperture through said workpiece simultaneously during said single stroke machining operation to form two opposing substantially planar surfaces.

An internal pull broach for working opposing walls of a rectangular slot in a workpiece during a single stroke machining operation comprising:

• an elongated cutting tool holder having a longitudinal axis and a lateral width, first and second surfaces on opposite longitudinally extending sides of said tool holder and a plurality of laterally extending, longitudinally spaced pockets in each of said first and second surfaces, each pocket extending laterally across substantially the entire width of the tool holder, said pockets laterally extending at an angle of approximately 5.degree. from normal with respect to said longitudinal axis of said tool holder, such that a leading edge of one pocket in said first surface is laterally opposite from a leading edge of a corresponding pocket in said second surface, said pockets divided into groups including a first pocket configuration and a second pocket configuration alternately disposed along a predetermined first longitudinal length of said tool holder, said first pocket configuration group having a first fastener means pattern and said second pocket configuration group having a second fastener means pattern different from said first pattern, and a third pocket configuration group disposed along a second longitudinal length of said tool holder adjacent one end, said third pocket configuration group having a third fastener means pattern different from said first and second patterns;
• first and second indexable cutter insert means for rough cutting said opposing walls of said workpiece, said first cutter insert means having a first set of chip breaking grooves and complementary first fastener means pattern with respect to said first pocket configuration group, said second cutter insert means having a second set of chip breaking grooves offset laterally from said first set and complementary second fastener means pattern with respect to said second pocket configuration group, said first and second cutter insert means alternately disposed in corresponding first and second group pockets along said first longitudinal length of said first and second surfaces;
• and
• third indexable cutter insert means for finish cutting said opposing walls of said workpiece, said third cutter insert means having a complementary third fastener means pattern with respect to said third pocket configuration group, such that each of said first, second and third cutter insert means is independently indexable and replaceable within a corresponding pocket, while being interchangeable only within a respective pocket configuration group, said first, second and third indexable cutter insert means engageable in said respective pocket groups and defining a plurality of sequentially acting, longitudinally spaced protuberances, each protuberance having a plurality of linear cutting edges and indexable within said respective pocket to orientate one cutting edge at a time in an operable position providing a single, linear, leading, cutting edge extending laterally with respect to said longitudinal axis substantially across an entire width of said tool holder for progressively cutting into said opposing walls of said aperture extending through said workpiece sequentially as said tool holder moves during said single stroke along a fixed linear path coaxial with said longitudinal axis of said tool holder extending through said aperture of said workpiece, said first, second and third indexable cutter insert means for roughing, semi-finishing and finishing said opposing walls of said aperture through said workpiece simultaneously during said single stroke machining operation to form two opposing substantially planar surfaces.