Tool for removing damaged fasteners and method for making such tool

A process for cold forming a tool for removing fasteners, said tool being cold formed from a tubular section that has a first end and a second end with an open passageway between the first and second ends, said tubular section defining a cylindrical inside surface between said first and second ends, said tubular section also defining a tapered outside surface that has an increasing diameter at longitudinal positions on the tubular section that are increasingly apart from the second end of the tubular section, said cold forming process comprising:

• driving a punch against the first end of the tubular section to place the tubular section into a die insert that is mounted in a die sleeve, said die insert being moveable with respect to said die sleeve in the direction of the longitudinal axis of the tubular section, the second end of said tubular section being driven onto a floating punch having helical splines that are located at the distal end thereof, said floating punch rotating in a first direction as the tubular section is driven onto the floating punch and the splines form complementary internal splines on the cylindrical inner surface of the tubular section;
• stripping the tubular section off of the floating punch by pushing against the second end of the tubular section with a stripper sleeve, said floating punch counter-rotating as the stripper sleeve presses on the second end of the tubular section and the tubular section travels to the end of the spline punch;
• extruding the tubular section through a round-to-polygonal extrusion die insert, said extruding step cold forming the tapered outer wall of the tubular section into a polygonal surface having substantially constant cross-section at longitudinal positions of the insert, said extruding step also cold forming the inside surface of the tubular section into a polygonal surface corresponding to the shape of the outside surface and that is tapered to provide a decreasing cross-section at longitudinal positions in the direction from the second end of the tubular section toward the first end of the tubular section to provide an inside surface having a tapered, polygonal shape with helical splines in the end of said inside surface that is adjacent the second end.

A process for cold forming a tool for removing a fastener, said tool being cold formed from a cutoff blank that is cut from a wire line, said process comprising:

• hitting the cutoff blank to square up the blank and to form a tapered outside surface for the blank;
• punching the tapered blank with an extrusion punch to form an extruded, tapered blank having a well in the cutoff blank by extruding metal in the cutoff blank in the direction past the extrusion punch, said well being on the same side of the cutoff blank as the extrusion punch;
• urging a hollow punch against the first end of the extruded, tapered blank to maintain the extruded, tapered blank in a die insert, that is slidably mounted in a die sleeve and mechanically biased toward one end of the die sleeve, said hollow punch urging the blank into the die insert and pushing the extruded tapered blank against a pierce punch, a second end of said extruded, tapered blank that is located oppositely from the bottom of the well in said extruded, tapered blank being pressed against the end of the pierce punch to pierce the second end of the extruded, tapered blank to form a tubular section with a tapered outside surface and a cylindrical inside surface;
• pushing on the first end of the tubular section when the tubular section is mounted in a die insert, that is slidably mounted in a die sleeve and mechanically biased toward one end of the die sleeve, said pushing step moving the tubular section away from the one end of the die sleeve and onto a floating punch that has helical splines at the end thereof, said floating punch rotating in a first direction and said helical splines interfering with the inside surface of the tubular section and forming internal helical splines in a portion of the inside surface of the tubular section adjacent the second end of the tubular section;
• relieving the force against the first end of the tubular section that opposes the bias force against the die insert;
• urging a kickout sleeve against the second end of the tubular section to strip the tubular section off of the splined end of the floating punch while the floating punch rotates in the direction that is the opposite direction from the first direction of rotation;
• and
• extruding the tubular section through a round-to-hexagonal extrusion die so that the tapered, round outer surface of the tubular section is cold formed to a hexagonal cross-section having substantially constant dimensions at position along the longitudinal axis of the tubular section, and also so that the inside surface of the tubular section is cold formed from a cylindrical surface to a surface that has a hexagonal cross-section with smaller dimensions at longitudinal positions away from the second end of the tubular section, the inner surface also having spiral-shaped splines in a portion of the inner surface that is adjacent to the second end of the tubular section.

A process for making a tool to remove damaged fasteners from threaded members, said tool being made in a cold forming machine having a plurality of forming stations that are arranged in a linear array, said cold forming machine having a punch assembly and a die assembly that correspond to each of said forming stations, said process comprising the steps of:

• cutting a solid blank from a wire line, said blank having a cylindrical surface that is defined between a first end and a second end;
• placing the blank in a punch die that defines a tapered surface and striking the first end of the blank with a punch to provide a tapered blank that has a round, tapered outer surface that is defined between a first end and a second end wherein the second end has a smaller cross-section than the first end;
• hitting the first end of the tapered blank with an extrusion punch and while the tapered blank is maintained in a die, said hitting step forming an extruded, tapered blank having a well therein by causing material of the tapered blank to be extruded between the perimeter of the extrusion punch and the die wall;
• piercing the extruded, tapered blank with a pierce punch, said pierce punch having an end cross-section that substantially corresponds to the area of the bottom of the well in the extruded, tapered blank, said pierce punch traveling through the second wall of the extruded, tapered blank at a position that is opposite from the bottom of the well, said pierce punch opening a center bore in the extruded, tapered blank in the direction of the longitudinal axis of the extruded, tapered blank to provide a tubular section having a cylindrical internal surface between first and second end surfaces and also having a tapered outer surface between the first and second end surfaces;
• driving a spline extrusion punch having a substantially constant radius into the bore of the tubular section from the second end of the tubular section to form internal splines on a portion of the inner surface of the tubular section that is adjacent the tapered end of said tubular section;
• and
• extruding the splined, tubular section through a round-to-polygonal extrusion insert to form a constant dimensioned outside wall for the tubular section and to form a polygonal inside wall having a tapered dimension and spiral-formed splines at the wide end of the inner surface of the tubular section.