Flat cutter bit with cutting insert having edge preparation
A flat cutter bit for engaging an earth strata material includes a non-rotatable shank portion, a head portion integrally formed with the non-rotatable shank portion and including a tip region distal from the non-rotatable shank portion, and a cutting insert mounted at the tip region of the head portion. The cutting insert includes a body having an angled leading face, a top surface having a relief surface, a T-land surface extending between the angled leading face and the relief surface of the top surface and a cutting edge formed at the intersection of the T-land surface and the relief surface of the top surface.
1. A flat cutter bit, the flat cutter bit comprising:
a non-rotatable shank portion;
a head portion integrally formed with the non-rotatable shank portion and including a tip region distal from the non-rotatable shank portion; and
a cutting insert mounted at the tip region of the head portion, wherein the cutting insert comprises:
a body having an angled leading face, wherein the angled leading face is planar;
wherein the body further includes a top surface having a relief surface, a bottom surface, a first side portion and a second side portion;
an arcuate T-land surface extending between the angled leading face and the relief surface of the top surface, wherein the arcuate T-land is contiguous with the angled leading face; and
an arcuate cutting edge formed only at the intersection of the arcuate T-land surface and the relief surface of the top surface,
wherein the arcuate T-land surface and the arcuate cutting edge extend continuously from the first side portion to the second side portion of the body.
2. The flat cutter bit of claim 1 , wherein the arcuate cutting edge has a negative axial rake angle.
3. The flat cutter bit of claim 2 , wherein the negative axial rake angle is in the range of about 10 degrees to about 60 degrees.
4. The flat cutter bit of claim 2 , wherein the arcuate T-land surface is positioned relative to the relief surface of the top surface at an angle that is greater than 90 degrees.
5. The flat cutter bit of claim 1 , wherein the arcuate cutting edge is rounded where the arcuate T-land surface intersects with the relief surface.
6. The flat cutter bit of claim 1 , wherein the arcuate T-land surface has a width in the range of about 0.002 inches to about 0.090 inches.
7. The flat cutter bit of claim 1 , wherein the angled leading face is on an upper section of the body.
8. The flat cutter bit of claim 7 , wherein the body also includes a lower section that has a generally circular cross-sectional shape.
9. A cutting insert for use in connection with a cutter bit, the cutting insert comprising:
a body having an angled leading face, wherein the angled leading face is planar;
wherein the body further includes a top surface having a relief surface, a bottom surface, a first side portion and a second side portion;
an arcuate T-land surface extending between the angled leading face and the relief surface of the top surface, wherein the arcuate T-land is contiguous with the angled leading face; and
an arcuate cutting edge formed only at the intersection of the arcuate T-land surface and the relief surface of the top surface,
wherein the arcuate T-land surface and the arcuate cutting edge extend continuously from the first side portion to the second side portion of the body.
10. The cutting insert of claim 9 , wherein the arcuate cutting edge has a negative axial rake angle.
11. The cutting insert of claim 10 , wherein the negative axial rake angle is in the range of about 10 degrees to about 60 degrees.
12. The cutting insert of claim 10 , wherein the arcuate T-land surface is positioned relative to the relief surface of the top surface at an angle that is greater than 90 degrees.
13. The cutting insert of claim 9 , wherein the arcuate cutting edge is rounded where the arcuate T-land surface intersects with the relief surface.
14. The cutting insert of claim 9 , wherein the arcuate T-land surface has a width in the range of about 0.002 inches to about 0.090 inches.
15. The cutting insert of claim 9 , wherein the angled leading face is on an upper section of the body.
16. The cutting insert of claim 15 , wherein the body also includes a lower section that has a generally circular cross-sectional shape.