Patent ID: 8763729

Claim:
An air-cooled hammer bit for drilling a borehole in earthen formations, the bit comprising: a bit body having a bit axis and a bit face with an outermost radius; a plurality of gage cutter elements mounted to the bit face in a circumferential gage row, wherein the circumferential gage row extends around the bit axis and wherein each gage cutter element is disposed at the same radial position relative to the bit axis; and a plurality of adjacent to gage cutter elements mounted perpendicular to the bit face in a circumferential row that is radially adjacent the gage row, wherein the circumferential adjacent to gage row extends around the bit axis and wherein each adjacent to gage cutter element is disposed the same radial position relative to the bit axis; each adjacent to gage cutter element and each gage cutter element having a cutting portion extending from the bit face, the cutting portion defining a cutting profile in rotated profile view; the cutting profile of each gage cutter element extending radially from an inner radius measured perpendicularly from the bit axis to an outer radius measured perpendicularly from the bit axis, wherein the cutting profile of each adjacent to gage cutter element extends radially from an inner radius measured perpendicularly from the bit axis to an outer radius measured perpendicularly from the bit axis, and wherein the inner radius of the cutting profile of each gage cutter element is less than the outer radius of the cutting profile of each adjacent to gage cutter element; and a radial distance between the inner radius of the cutting profile of each adjacent to gage cutter element and the outer radius of the cutting profile of each gage cutter element defining a radial span distance, and a radial distance between the inner radius of the cutting profile of each gage cutter element and the outer radius of the cutting profile of each adjacent to gage cutter element defining a radial overlap distance, wherein the ratio of the radial overlap distance to the radial span distance is greater than 0.25.