Chicago-Latrobe 46491 135° Cobalt Jobber Drill 10.8 mm

10.8 mm Cobalt Jobber Drill

This 10.8 mm cobalt jobber drill bit is designed for drilling hard metals such as stainless steel and high-strength alloys. The 135-degree split point reduces walking and starts the cut immediately without a centre punch. It suits maintenance technicians and metal fabricators who need a durable bit for repeated use in tough materials. The straw-bronze surface finish identifies the cobalt construction and aids chip evacuation.

Sustained drilling in hard alloys

Cobalt steel retains hardness at the elevated temperatures generated during prolonged drilling in tough alloys. The 135-degree point angle distributes cutting forces evenly, which slows wear on the cutting lips when the bit is used continuously. Split-point geometry keeps the bit centred through deep holes, reducing the risk of breakage under steady feed pressure. No internal coolant holes are present, so external lubrication is required for extended operations.

Installation and common issues

The straight shank fits standard three-jaw drill chucks without adapters. Tighten the chuck securely on the shank flats to prevent spin-out under high torque. Because the bit lacks coolant-through channels, apply cutting fluid frequently to avoid overheating and premature dulling. The split point eliminates the need for centre punching on most materials, but a light punch mark helps on very hard or rounded surfaces.