Cleveland C73421 Jobber Drill Bit 25/64 Inch Hss

Product Description

The CLEVELAND C73421 is a jobber-length twist drill bit designed for production drilling in metal fabrication, maintenance, and general trade work. Built from high speed steel with a bright uncoated finish, it features a 118-degree split point that reduces walking and lowers the thrust required to enter the workpiece. The 25/64-inch diameter (0.3906 inches decimal) and right-hand spiral flute geometry make it well suited for through-hole and blind-hole drilling in a wide range of base materials. At 5-1/8 inches overall length with a 3-3/4-inch flute length, it fits standard drill chucks and magnetic-base drill setups used across the trades.

The C73421 is rated heavy duty under the NAS 907 Type A specification, placing it in a class appropriate for consistent production use rather than light-duty occasional drilling. Primary workpiece material noted by the manufacturer is aluminum, though the high speed steel construction handles steel, cast iron, plastics, and composite materials in typical shop and field conditions. The straight-cylindrical shank at 0.3906 inches diameter seats securely in both keyed and keyless chucks. It is sold individually and is a standard stocking size for tool cribs, service vans, and job-site tool kits.

Key Features

• 25/64-inch diameter (0.3906 inches decimal) with tight diameter tolerance of -0.0010 to 0.0000 inches
• 118-degree split point reduces bit walking and lowers drilling thrust
• High speed steel construction with bright uncoated finish for general-purpose use
• Right-hand regular spiral flute, 3-3/4 inches long, for efficient chip evacuation
• Web-thinned tapered web for reduced cutting resistance
• Meets NAS 907 Type A standard; heavy-duty grade rating
• Straight-cylindrical shank fits standard drill chucks without adapters

Compatibility

Designed as a standard jobber-length replacement drill bit conforming to NAS 907 Type A specifications, compatible with any keyed or keyless chuck accepting a 0.3906-inch straight-cylindrical shank.

Installation Notes

Installation of drill bits should be performed with the drill unplugged or the air supply disconnected before changing tooling. Seat the shank fully into the chuck and tighten evenly using the chuck key before applying power. Use appropriate cutting fluid or lubricant when drilling ferrous metals to extend bit life. Follow applicable OSHA and shop safety standards for eye protection and workpiece clamping.