Broaching tool and method of manufacture

A method of making a broaching tool, the method comprising:

• creating one or more teeth, wherein creating each tooth comprises:
• providing a tooth blank that defines a front face and an opposite rear face;
• using electrical discharge machining to define a lobed cutting surface in the tooth blank having a first interface where the lobed cutting surface meets the front face and a second interface where the lobed cutting surface meets the rear face;
• and
• varying the position of an electrical discharge machining electrode when defining the lobed cutting surface such that a tool clearance offset is formed in the lobed cutting surface rearward of the first interface, wherein the tool clearance offset is substantially continuous along the entire lobed cutting surface.

A broaching assembly comprising:

• a tool body having a tool retention channel;
• a first tooth comprising:
• a front face;
• a rear face opposite the front face;
• a first cutting surface having a fir tree shape extending along a first side of the first tooth between the front face and the rear face of the first tooth, such that a first interface defined between the first cutting surface and the front face is offset relative to a second interface defined between the first cutting surface and the rear face in a direction that is substantially perpendicular to an axis of tooth movement for broaching operations to provide tool clearance rearward from the first interface;
• a second cutting surface having a fir tree shape extending along a second side of the first tooth located opposite the first side;
• and
• a first attachment notch at a location spaced from the first and second cutting surfaces;
• a second tooth positioned adjacent to the first tooth, the second tooth comprising:
• a front face;
• a rear face opposite the front face;
• a third cutting surface having a fir tree shape extending along a first side of the second tooth between the front face and the rear face of the second tooth such that a third interface defined between the third cutting surface and the front face is offset relative to a fourth interface defined between the third cutting surface and the rear face in a direction that is substantially perpendicular to an axis of tooth movement for broaching operations to provide tool clearance rearward from the third interface;
• and
• a second attachment notch at a location spaced from the third cutting surface
• a spacer positioned between the first tooth and the second tooth and defining an outer perimeter surface that is smaller than any teeth retained in the tool retention channel such that the spacer will not contact a workpiece during a broaching operation, wherein the spacer includes a spacer attachment notch;
• a clamp at least partially inserted into each of the first and second attachment notches and the spacer attachment notch to commonly retain the first tooth, the second tooth and the spacer at least partially within the tool retention channel of the tool body, wherein the clamp is secured to the tool body with at least one fastener.