Drill bit
AssigneeOmark Industries, Inc.
InventorFrederic G. Croydon
Life of this patent
Estimating the term…
Abstract
A drill bit having a generally cylindrical body with a working end and flutes extending along the body. The working end is formed with a central work-engaging point and a pair of slitting spurs spaced outwardly from the point adjacent edge margins of the body. Convexly contoured portions interconnect the point and spurs to permit sharpening with a round file.
Claims5
A drill bit comprising an elongate body having a working end and helical flutes formed therein extending from said working end toward the opposite end of said body, said working end being formed with a central work-engaging point, at least a pair of slitting spurs spaced radially outwardly from said point adjacent outer edge margins of said body, and a convexly contoured body portion interconnecting said point and a spur and intersecting a flute in said body to define a sharpened cutting edge intermediate said point and spur, a spur having a sharpened arcuate slitting edge directed longitudinally outwardly from said body in the same direction as said point with a leading portion of said slitting edge which first engages the work on rotation of the drill sloping toward the opposite end of said body on progressing in the direction of rotation.
Dependencies are inferred from the claim text.