초록 ▼

A drill/reamer bit is described that is particularly suitable for high speed operation and which comprises a bit having a “split”pilot or drill portion with four facets and two cutting edges on each web and a “step”or reamer portion having two reliefs and one cutting edge associated with each web, t

A drill/reamer bit is described that is particularly suitable for high speed operation and which comprises a bit having a “split”pilot or drill portion with four facets and two cutting edges on each web and a “step”or reamer portion having two reliefs and one cutting edge associated with each web, the webs being formed by a pair of flutes angled at from approximately 8½°to approximately 23°, the bit being formed primarily of fine grain tungsten carbide material, the drill portion having an included angle of approximately 118±2 degrees.

대표청구항 ▼

A drill bit having a pair of spiral flutes separated by a pair of webs, each of said webs terminating at the cutting end of said bit in first, second, third, and fourth facets, a trailing edge and primary and secondary cutting edges contained in the plane of said first facet, each of said webs havin

A drill bit having a pair of spiral flutes separated by a pair of webs, each of said webs terminating at the cutting end of said bit in first, second, third, and fourth facets, a trailing edge and primary and secondary cutting edges contained in the plane of said first facet, each of said webs having a step floor extending from the periphery of said webs to a smooth wall, said wall extending parallelly to the drill axis from said step floor to said facets, and a relief in said step floor intersecting with said flute surface thus to constitute a reamer cutting edge.