US Patent 7264427 Drill bit apparatus

A drill bit apparatus having a central shaft and an annular collar mounted thereon. The central shaft is coaxially positioned within the annular collar. The central shaft has a bit end and a cutting tool end. The annular collar is spaced between the bit and cutting tool end. The bit is configured for releasable securement in a chuck of a drill or drill press. The cutting tool end is configured to securably receive a cutting tool therein. The cutting tool lower portion has a central bore cutter essentially coaxial with the shaft. The upper portion of the tool comprises a counter bore cutter having a width greater than the central bore cutter. The counter bore cutter extends below a lower surface of the annular collar a distance less than the distance the central bore cutter extends below the lower surface.