Cleveland C70047 Cobalt Jobber Drill Bit 8.43mm 135

Product Description

The CLEVELAND C70047 is a cobalt jobber length drill bit designed for high-performance drilling in tough materials. Built from M42 cobalt high-speed steel and finished with a gold oxide coating, it delivers superior heat and wear resistance compared to standard HSS bits. The bit measures 8.43 mm (0.3320 inch) in diameter with an overall length of 4.75 inches and a flute length of 3.4375 inches. The 135-degree split point self-centers on contact, reducing walking and the need for a center punch. A tapered web with web thinning reduces thrust and improves chip evacuation. Licensed machinists, maintenance technicians, and metalworking professionals install this bit in standard drill presses and hand-held power drills.

This drill bit is suited for use in aluminum and other non-ferrous and ferrous workpiece materials where heat buildup and tool wear are concerns. It is built to NAS 907 Type J standards, making it appropriate for aerospace-adjacent and industrial maintenance applications. The straight cylindrical shank seats in standard three-jaw chucks without requiring a special collet or adapter. The regular spiral flute geometry and right-hand cutting direction are consistent with the majority of benchtop and floor-standing drill presses used in production and job-shop environments.

Key Features

• M42 cobalt steel construction for elevated heat resistance and extended tool life in hard or abrasive materials
• Gold oxide coating reduces friction and surface wear during high-speed drilling operations
• 135-degree split point self-centers and reduces thrust, eliminating the need for a center punch on most surfaces
• Web-thinned tapered web lowers cutting resistance and improves chip flow through the flute channel
• Right-hand spiral flute with regular helix geometry for efficient chip evacuation
• Meets NAS 907 Type J specification for consistent dimensional and performance standards

Compatibility

Designed as a heavy-duty OEM-style jobber drill bit compatible with standard straight-shank three-jaw chucks. Fits drill presses, hand drills, and CNC drilling equipment accepting a 0.3320-inch straight cylindrical shank.

Installation Notes

Installation is performed by machinists or maintenance technicians familiar with rotating cutting tools. Before inserting or removing the bit, ensure the drill press or power tool is fully powered down and the chuck key is clear of the chuck. Secure the shank firmly in the chuck to the full depth of the jaws to prevent runout. Do not exceed the recommended speed and feed for the workpiece material, and use appropriate cutting fluid when drilling ferrous metals to extend tool life.