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, wherein the chip flute includes a chip gash opening extending from the rearward end toward the forward end of the cutting portion, and wherein the chip gash opening is defined by a recessed bottom surface, a front wall formed with a radius, R2, and opposing side walls.

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 recessed bottom surface, 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, a radially-inward side surface, a forward side surface, a radially-outward side surface and a rearward side surface, wherein a leading edge is formed at an intersection between the top surface and the radially-outward side 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 top surface includes a chip breaker having a bottom surface formed with a radius, R.