Cleveland C15939 Jobber Drill Bit Wire 11 Cobalt M42

Product Description

The CLEVELAND C15939 is a jobber-length drill bit designed for demanding metal-cutting applications. Built from M42 cobalt high-speed steel with an oxide coating, it handles superalloys, stainless, and other hard materials where standard HSS bits fail. The split-point, web-thinned tip at 135 degrees reduces walking and lowers thrust on entry, making it a go-to for production drilling without a center punch. Overall length is 3.5 inches, with a 1.1875-inch flute length and a straight-cylindrical shank diameter of 0.1910 inches. Licensed trades and machining shops rely on this bit for consistent, repeatable hole quality in tight-tolerance work.

Wire size 11 corresponds to a decimal diameter of 0.1910 inches, placing it in the 0.1500 to 0.2000 inch range commonly used for clearance holes, tap-drill applications, and close-tolerance bores in ferrous and non-ferrous metals. The fast spiral flute promotes chip evacuation in deeper cuts. Series 3780 is a heavy-duty designation built to ASME B94.11M standards, making it appropriate for both manual drill press work and CNC drilling cycles where tool rigidity and runout control matter.

Key Features

• M42 cobalt steel construction rated for superalloy and hard-metal drilling
• 135-degree split point with web thinning reduces thrust and eliminates pilot drilling
• Oxide coating provides lubricity and mild corrosion resistance during cutting
• Fast spiral flute design promotes aggressive chip clearance
• Straight-cylindrical shank fits standard drill chucks without adapters
• Meets ASME B94.11M and NAS specification requirements

Compatibility

Designed as an OEM-style replacement or direct-use jobber bit for any drill press, hand drill, or CNC spindle accepting a 0.1910-inch straight-cylindrical shank. Suitable for drilling superalloys, stainless steel, hardened steels, and similar hard ferrous materials.

Installation Notes

Secure the shank fully in a keyed or keyless chuck and verify runout before drilling. For best tool life in superalloy applications, use cutting fluid and avoid dwelling at reduced feed, which work-hardens the material. When used in a CNC setup, confirm spindle speed and feed rate match the workpiece material and bit diameter per standard machining tables. Inspect the cutting edges before each use; cobalt bits can fracture if chipped and run further.