Cleveland C15146 Letter Q Cobalt Screw Machine Drill Bit

Product Description

The CLEVELAND C15146 is a screw machine length drill bit sized to Letter Q (0.3320 inches) and manufactured from M42 cobalt high-speed steel. The 135-degree split point with web thinning starts on contact without a center punch, reducing walking and thrust on hard materials. A parabolic flute geometry promotes aggressive chip evacuation, making this bit well-suited for interrupted cuts and deep-hole work in tough stock. The straight-cylindrical shank measures 0.3320 inches in diameter with a shank length of 1.3125 inches. Overall length is 3.0 inches, consistent with screw machine length standards for short, rigid setups. This bit is designed for use by machinists and metalworking tradespeople on drill presses, CNC machining centers, and turret lathes.

The C15146 is intended for drilling alloy steels and aluminum in production and job-shop environments where tool life under heat and pressure is critical. The M42 cobalt grade (8 percent cobalt content) offers superior red hardness compared to standard M2 HSS, extending bit life when cutting work-hardened or abrasive materials without coolant through the tool. The screw machine length format keeps the tool short and stiff, minimizing deflection in close-tolerance applications typical of production drilling fixtures.

Key Features

• Letter Q size: 0.3320 inches diameter with a tolerance of +0.0000 to -0.0010 inches
• M42 cobalt construction for extended tool life in alloy steel and aluminum
• 135-degree split point with web thinning for self-centering starts and reduced thrust
• Parabolic flute design promotes efficient chip evacuation in deep holes
• Screw machine length (3.0 inches OAL) provides rigidity and minimizes runout
• Right-hand cut with straight-cylindrical shank fits standard drill chucks and collets
• Meets ASME B94.11M standards; Series 2175A

Compatibility

Designed as a screw machine length replacement or production drill bit for use in standard drill chucks and collets accepting a 0.3320-inch straight-cylindrical shank, compatible with primary workpiece materials including alloy steel and aluminum per Series 2175A specifications.

Installation Notes

A licensed machinist or qualified metalworking technician should install and operate this drill bit. Secure the shank fully in a properly sized chuck or collet before starting the spindle. Verify spindle speed and feed rate are appropriate for the workpiece material and bit diameter before commencing drilling. Do not force the bit through hardened material beyond its rated grade capability, and inspect for wear or chipping before each use.