Multi-flute reamer and cutting insert therefor

A multi-flute reamer, comprising:

• a cutting portion having a forward end and a rearward end and a peripheral surface therebetween, the cutting section including a chip flute that extends rearwardly from the forward end, the chip flute including a chip gash opening extending from the rearward end toward the forward end of the cutting portion, wherein the chip gash opening is defined by a bottom surface recessed relative to the chip flute, a front wall formed with a radius, R2, and opposing side walls;
• and
• a cutting insert mounted on the cutting portion, the cutting insert including a top surface, a bottom surface opposite the top surface, a radially-inward side surface extending from the top surface to the bottom surface, a forward side surface extending from the top surface to the bottom surface, a radially-outward side surface extending from the top surface to the bottom surface and a rearward side surface extending from the top surface to the bottom surface, wherein a leading edge is formed at an intersection between the top surface and the radially-outward side surface, and wherein the radially-outward side surface includes a first facet surface extending from the leading edge to a second facet surface, the second facet surface extending from the first facet surface to the bottom surface, and wherein a front edge is formed at an intersection between the top surface and the forward side surface, and wherein the cutting insert further includes a rounded lead cutting edge formed with a radius, R1, at the intersection between the leading edge and the front edge, and wherein the cutting insert further comprises a primary relief surface and a secondary relief surface, wherein the primary relief surface extends between the rounded lead cutting edge and the secondary relief surface, and wherein the secondary relief surface extends from the bottom surface to the primary relief surface.