ALEXANDRIA, Va., Jan. 20 -- United States Patent no. 12,528,128, issued on Jan. 20, was assigned to SUMITOMO ELECTRIC HARDMETAL CORP. (Itami, Japan).
"Drill" was invented by Naohiro Nakamura (Itami, Japan).
According to the abstract* released by the U.S. Patent & Trademark Office: "A drill has a helical flute surface, a flank face, and a thinning face. A ridgeline between the thinning face and the flank face constitutes a thinning cutting edge. The thinning cutting edge has a curved thinning cutting edge portion and a straight thinning cutting edge portion. The curved thinning cutting edge portion protrudes forward in the rotation direction. The straight thinning cutting edge portion is contiguous to the curved thinning cutting edge porti...