Cleveland Golf 21/64 Cobalt Jobber Drill Bit 135° Split Point Black Oxide

Cleveland Golf 21/64 Cobalt Jobber Drill Bit

This Cleveland Golf jobber drill bit is a fractional-inch cutting tool made from cobalt steel with a black oxide finish. It is designed for drilling alloy, carbon, stainless, and tool steels in professional workshop or industrial maintenance environments. The heavy-duty grade construction suits users who need reliable performance on tough materials.

135-degree split point and 4xD depth ratio

The 135-degree split point geometry reduces walking and allows the bit to start on contact without a centre punch. A depth-to-diameter ratio of 4xD defines the practical drilling limit for this flute length, so holes deeper than roughly four times the diameter will require pecking or a longer series drill. The right-hand spiral flute clears chips effectively in standard through-hole applications.

Check shank fit and material compatibility

Verify that your drill chuck or collet accepts a 21/64-inch shank, as the shank diameter matches the drill diameter exactly. Confirm the workpiece material falls within the listed alloy, carbon, stainless, and tool steel range; the bit is not rated for non-ferrous metals or hardened steels beyond the specified scope. Ensure your machine provides rigid spindle alignment to maintain the split point's self-centering benefit.