Drill bit arcuate-shaped inserts with cutting edges and method of manufacture

A bit for drilling a borehole into earthen formations, the bit comprising;

• a bit body;
• a rolling cone cutter rotatably mounted on said bit body and being adapted to rotate about a cone axis;
• a groove formed in said cone cutter arid extending completely around said cone axis;
• a ring-shaped insert having a 360° arcuate length, said insert having a radially innermost side surface, a radially outermost side surface, and a cutting surface extending between said side surfaces, said cutting surface including a plurality of cutting edges.

A bit for drilling a borehole into earthen formations, the bit comprising;

• a bit body;
• a rolling cone cutter rotatably mounted on said bit body and being adapted to rotate about a cone axis;
• a groove formed in said cone cutter and extending completely around said cone axis;
• a ring-shaped insert having a 360° arcuate length and a cutting surface, said ring shaped insert retained in said groove;
• wherein said cutting surface includes a plurality of cutting edges;
• and
• wherein said cutting surface comprises a plurality of non-radially aligned grooves forming a first plurality of cutting edges having negative backrake angles and a second plurality of cutting edges having positive backrake angles.

A method for manufacturing a rolling cone drill bit comprising:

• providing a rolling cone cutter having a cone axis;
• forming a groove in said cone cutter;
• providing a cutter insert having an arcuate-shaped base portion and a cutting portion, said cutter insert having a radially innermost side sur face, a radially outermost side surface, and a cutting surface extending between said side surfaces, said cutting surface including a plurality of cutting edges;
• after providing said cutter insert having said arcuate-shaped base portion, fixing said insert into said cone cutter by press fitting said base portion into said groove.

A method for manufacturing a drill bit comprising:

• providing a rolling cone cutter having a cone axis, a backface, a generally frustoconical heel surface adjacent said backface, and a generally conical surface adjacent to said heel surface;
• forming a cutter insert having a 360° arcuate length and a cutting surface that comprises a plurality of cutting edges disposed along said length;
• forming a circumferential groove in said cone cutter;
• and
• after forming said cutter insert, press fitting said cutter insert into said circumferential groove.

A bit for drilling a borehole into earthen formations, the bit comprising;

• a bit body;
• a rolling cone cutter rotatably mounted on said bit body and being adapted to rotate about a cone axis;
• a groove formed in said cone cutter and extending completely around said cone axis;
• a ring-shaped insert having a 360° arcuate length and a cutting surface, said cutting surface including an inner annular surface, an outer annular surface, and a plurality of cutting edges extending at least partially across the inner annular surface and at least partially across the outer annular surface;
• and
• wherein the ring-shaped insert is retained by interference fit within said groove.