Cleveland C15927 Jobber Drill Bit Wire 21 Cobalt 135 Deg

Product Description

The CLEVELAND C15927 is a cobalt jobber-length drill bit sized to wire gauge #21 (0.1590 inches diameter). Built from M42 cobalt high-speed steel with an oxide coating, it is designed for heavy-duty drilling in superalloys, stainless steel, and other tough materials. The 135-degree split point reduces walking at startup and lowers thrust force. A fast-spiral, two-flute design with a web-thinned, tapered web improves chip evacuation and cutting efficiency. Overall length is 3.25 inches with a flute length of 1.0625 inches and a straight-cylindrical shank of 0.1590 inches diameter. It conforms to ASME B94.11M and carries a NAS specification designation.

This bit is suited for production and maintenance drilling operations where standard high-speed steel bits wear prematurely. Typical applications include aerospace component work, industrial maintenance, and precision metalworking where superalloy, heat-resistant alloy, and hardened steel workpieces are encountered. The right-hand cutting direction and fast spiral make it appropriate for use in handheld drill motors, drill presses, and CNC setups handling difficult-to-machine materials. Series 3780 bits are classed as heavy-duty grade for demanding shop environments.

Key Features

• M42 cobalt HSS construction resists heat buildup in hard and superalloy materials
• 135-degree split point starts on contact, reducing drill walking and required thrust
• Oxide coating provides additional surface hardness and lubricity
• Fast-spiral, two-flute geometry promotes efficient chip removal
• Web-thinned tapered web reduces cutting resistance at the center of the bit
• Straight-cylindrical shank fits standard drill chucks without adapters
• Conforms to ASME B94.11M; NAS specification designation; Heavy Duty grade

Compatibility

Designed as a heavy-duty replacement or stock bit for applications requiring a wire gauge #21 (0.1590 inches) diameter hole in superalloys, stainless, and similarly hard metals. Fits any standard drill chuck accepting a 0.1590-inch straight-cylindrical shank.

Installation Notes

This bit is installed by machinists, toolroom technicians, and industrial maintenance trades using drill presses, mill-drill machines, or hand drills. Secure the straight shank firmly in the chuck before use. Use appropriate cutting fluid or coolant — note this bit does not support coolant-through delivery — and ensure workpiece is clamped securely to prevent movement during drilling. Inspect the cutting edges for wear after use in superalloy materials, as even cobalt bits experience accelerated edge wear in high-nickel alloys.