Cleveland C11631 Jobber Drill Bit Letter B Hss

Product Description

The CLEVELAND C11631 is a jobber-length drill bit sized at Letter B (0.2380 inches) and manufactured from high speed steel with a bright, uncoated finish. It features a 135-degree split point that reduces walking on entry and lowers the thrust required to start a hole. The web-thinned, tapered web construction improves chip evacuation and cutting efficiency. Two spiral flutes with a regular helix run 2.75 inches in length along a straight-cylindrical shank. With a 4-inch overall length and a heavy-duty grade designation, this bit is built for production drilling and general metalworking tasks performed by machinists, maintenance technicians, and fabrication shops.

This bit is rated for use on aluminum as its primary workpiece material, making it well suited for HVAC sheet metal work, electrical enclosure fabrication, and light structural assemblies where clean, accurate holes in aluminum are required. The straight-cylindrical shank seats directly into standard drill chucks without adapters. It conforms to NAS 907 Type B standards, which specify dimensional tolerances and geometry for jobber-length bits used in aerospace and industrial applications. Diameter tolerance is held to -0.0007 to 0.0000 inches, ensuring consistent fit in close-tolerance applications.

Key Features

• Letter B diameter: 0.2380 inches with tolerance of -0.0007 to 0.0000 inches for close-tolerance hole work
• 135-degree split point reduces entry walking and lowers drilling thrust
• Web-thinned, tapered web construction improves chip flow and reduces heat buildup
• High speed steel construction withstands the heat generated in continuous drilling cycles
• Bright, uncoated finish suitable for use with cutting fluids on aluminum and similar non-ferrous materials
• Meets NAS 907 Type B standards for geometry and dimensional consistency

Compatibility

Designed as an OEM-style jobber-length replacement drill bit for use in standard drill chucks accepting straight-cylindrical shanks at 0.2380 inches diameter; primary workpiece material rating is aluminum per manufacturer specification.

Installation Notes

Installation is performed by machinists, maintenance technicians, or fabricators using a standard drill press, hand drill, or CNC spindle with a compatible chuck. Secure the shank fully in the chuck and verify concentricity before drilling. Apply an appropriate cutting fluid for aluminum to extend bit life and improve hole finish. Inspect the cutting edges and split point for wear or chipping before each use and replace the bit if geometry is degraded.