Abstract: A hammer bit includes a bit body having a bit axis and a bit face, a first circumferential row of cutting elements mounted to the bit face, the first circumferential row located at an outermost radius of the bit face and extending around the bit axis, and a second circumferential row of cutting elements mounted to the bit face, the second circumferential row located radially inwardly adjacent the first circumferential row, wherein each of the cutting elements of the second circumferential row is a semi-round top insert. The ratio of the radial overlap distance to the radial span distance between the cutting profiles of cutting elements of the first and second circumferential rows is between 0.1 and 0.5. The ratio of the radial overlap distance to the radial span distance between the cutting profiles of the first and second circumferential rows is greater than 0.25.

Abstract: A percussion drill bit for drilling a borehole. The drill bit includes a bit body having a bit face disposed on an axial end portion thereof. First and second cutting elements are disposed on the bit face. A cutting plane is defined in tangential contact with crest portion of the first and second cutting elements. A third cutting element on the bit face is at least partially positioned between the first and second cutting elements. The third cutting element is at least partially conical, and a crest portion of the third cutting element is offset from the cutting plane.

Abstract: A cutting insert for a percussion hammer bit. The cutting insert includes a base portion for coupling to a bit face of the percussion hammer bit. An extension portion is coupled to the base portion and axially offset therefrom along a longitudinal axis extending through the base portion and the extension portion. The extension portion includes at least three lobes that are circumferentially offset from one another around the longitudinal axis. The lobes extend axially away from the base portion, and the lobes extend radially outward from the longitudinal axis.

Abstract: A hammer bit for drilling a borehole in earthen formations includes a bit body having a bit axis and a bit face, a plurality of gage cutter elements mounted to the bit face in a circumferential gage row, and a plurality of adjacent to gage cutter elements mounted to the bit face in a circumferential row that is radially adjacent the gage row. The ratio of the radial overlap distance to the radial span distance between radially overlapping gage cutter elements and adjacent to gage cutter elements is greater than 0.25. The ratio of the radial overlap distances to the diameter of the gage cutter element is greater than 0.25. An average cutting area of the gage cutter elements per gage cutter element is less than an average surface area of an entire cutting surface of each of the gage cutter elements.

Abstract: A hammer bit for drilling a borehole in earthen formations comprises a bit body having a bit axis and a bit face. The bit face includes an inner region extending from the bit axis to about 50% of the bit radius and an outer region extending from the inner region to the outermost radius. In addition, the bit comprises a plurality of gage cutter elements mounted to the bit face in a circumferential gage row in the outer region. Further, the bit comprises a plurality of adjacent to gage cutter elements mounted to the bit face in a circumferential adjacent to gage row in the outer region. The cutting profile of at least one cutter element in each row in the outer region radially overlaps with the cutting profile of at least one other cutter element in a different row in rotated profile view.

Abstract: A hammer bit for drilling a borehole in earthen formations. In an embodiment, the bit comprises a bit body having a bit axis and a bit face. The bit face includes an inner region extending from the bit axis to about 50% of the bit radius and an outer region extending from the inner region to the outermost radius. In addition, the bit comprises a plurality of gage cutter elements mounted to the bit face in a circumferential gage row in the outer region. Further, the bit comprises a plurality of adjacent to gage cutter elements mounted to the bit face in a circumferential adjacent to gage row in the outer region. The cutting profile of at least one cutter element in each row in the outer region radially overlaps with the cutting profile of at least one other cutter element in a different row in rotated profile view.