Cleveland C70055 Cobalt Jobber Drill Bit 10.26 Mm

Product Description

The CLEVELAND C70055 is a cobalt jobber length drill bit designed for heavy-duty drilling in aluminum and other demanding workpiece materials. Built from M42 cobalt high-speed steel, this bit features a gold oxide coating that reduces friction and extends tool life in high-heat applications. The 135-degree split point starts on contact without a center punch, reducing walking on hard or slick surfaces. With a right-hand spiral flute and web-thinned, tapered web configuration, it clears chips efficiently during through-hole drilling. Licensed HVAC techs, plumbers, electricians, and mechanical contractors will find this bit well-suited for structural and sheet metal drilling tasks in the field or shop.

The C70055 is sized at 10.26 mm (0.4040 inches) in diameter with an overall length of 5.25 inches and a flute length of 3.875 inches. The straight-cylindrical shank measures 0.4040 inches in diameter and 1.375 inches in length, making it compatible with standard drill chucks and driver setups. It conforms to NAS 907 Type J standards. Primary workpiece material is aluminum, though M42 cobalt construction also handles stainless steel, cast iron, and other abrasive materials that would wear down standard HSS tooling more quickly.

Key Features

• M42 cobalt construction provides heat resistance and hardness retention in heavy-duty drilling
• Gold oxide coating reduces friction and guards against chip welding in aluminum
• 135-degree split point eliminates need for center punching and improves bite on smooth surfaces
• Web-thinned tapered web improves chip evacuation and reduces thrust load
• Right-hand regular spiral flute clears chips consistently in through-hole applications
• Meets NAS 907 Type J specification for precision and dimensional consistency

Compatibility

Designed as an OEM-style replacement or upgrade for standard jobber length drill bits in the 0.4000 to 0.5000 inch (10.00 to 12.50 mm) size range. Part of the CLEVELAND Series 2213 heavy-duty cobalt drill bit line conforming to NAS 907 Type J standards.

Installation Notes

Install into a standard drill chuck rated for straight-cylindrical shanks, ensuring the chuck jaws are clean and fully tightened before use. Always wear appropriate eye protection and secure the workpiece before drilling. Match drill speed (RPM) to the workpiece material and bit diameter using a standard speeds-and-feeds reference. Do not use excessive force to feed the bit, as cobalt tooling is harder but can be brittle under lateral loading.