Cleveland Golf Jobber Drill 1/8 In Cobalt Black Oxide 135 Deg 3780

Jobber Drill Bit for Metalworking

This cobalt steel jobber drill bit measures 1/8 inch in diameter with a 135-degree split point for self-centering starts. The black oxide finish adds lubricity and resists corrosion during heavy-duty drilling. It suits machinists and maintenance technicians cutting alloy, carbon, stainless or tool steels. The 2-3/4 inch overall length and 7/8 inch flute length provide a 4xD depth-to-diameter ratio.

Thermals Noise and Power Draw

Cobalt steel retains hardness at elevated temperatures generated when drilling tough alloys, reducing premature wear. The black oxide surface holds cutting fluid to lower friction and heat buildup in the cut zone. Spiral flutes evacuate chips efficiently, preventing packing that increases torque and motor load. Right-hand cutting direction matches standard drill press and handheld drill operation.

Upgrade From High-Speed Steel Bits

This bit replaces general-purpose high-speed steel drills that dull quickly in stainless or tool steel. The heavy-duty cobalt construction justifies the step up when hole counts rise or material hardness exceeds HSS capability. Shops drilling occasional mild steel will not see proportional benefit over standard bits. The split-point geometry eliminates the need for centre punching in many setups.