Cleveland C16523 Jobber Length Drill Bit Wire 21 Cobalt

Product Description

The CLEVELAND C16523 is a jobber-length twist drill bit in wire gauge size 21, producing a hole diameter of 0.1590 inches. Built from M42 cobalt high-speed steel with a gold oxide coating, it is designed for heavy-duty drilling in demanding materials including cast iron, stainless steel, carbon steel, and non-ferrous metals. The 135-degree split point reduces walking on entry and lowers thrust requirements compared to a conventional 118-degree point. A parabolic flute geometry improves chip evacuation and reduces heat buildup during deeper cuts. This bit is part of the Cleveland Series 2075 and is sized for use in standard drill chucks and CNC drilling operations.

The C16523 is suited for production and maintenance drilling in metalworking shops, fabrication environments, and field service applications. Its straight-cylindrical shank accepts standard drill chucks without adapters. The heavy-duty M42 cobalt grade makes it a reliable choice when high-speed steel tooling falls short on hardened or abrasive materials. Machinists, tool and die technicians, and industrial maintenance mechanics are the primary users. It is sold individually and is appropriate for both manual drill press and CNC spindle use.

Key Features

• M42 cobalt steel construction for heat resistance and edge retention in hard materials
• 135-degree split point reduces drill walking and entry thrust
• Parabolic flute design promotes efficient chip evacuation in deep holes
• Gold oxide finish provides lubricity and surface hardness at the cutting edge
• Web-thinned tapered web reduces cutting resistance and heat generation
• Straight-cylindrical shank fits standard 3-jaw chucks and collet holders without adapters

Compatibility

Designed for drilling cast iron, non-ferrous metals, stainless steel, and carbon steel. Conforms to ASME B94.11M and DIN 338 standards. Diameter tolerance is -0.0007 to 0.0000 inches, consistent with standard jobber-length drill specifications.

Installation Notes

Secure the shank fully in the chuck before drilling and verify runout before production use. Apply cutting fluid rated for the workpiece material, particularly when drilling stainless steel or cast iron, to extend tool life and maintain hole tolerance. Reduce feed rate and spindle speed relative to standard HSS recommendations when first using a new bit on hardened or abrasive alloys. Always wear appropriate eye protection and ensure the workpiece is firmly clamped or fixtured before beginning the cut.