Cleveland C14284 Screw Machine Drill Bit Letter D Cobalt

Product Description

The CLEVELAND C14284 is a screw machine length cobalt drill bit sized to Letter D (0.2460 inches) and built for heavy-duty drilling in tough materials. It features a 135-degree split point that reduces walking on contact and cuts through workpieces with less feed pressure than a conventional 118-degree point. The parabolic flute geometry improves chip evacuation during deep-hole drilling. At 2.5 inches overall length, the screw machine (stub) length format provides added rigidity over jobber-length bits, making it well-suited for CNC machining centers, drill presses, and turret lathes where chatter control matters.

This bit is designed for drilling alloy steels and aluminum in production machining environments. The straight-cylindrical shank at 0.2460 inches diameter fits standard drill chucks and collet systems without modification. The cobalt (M42) construction retains hardness at elevated cutting temperatures, which makes it a practical choice for interrupted cuts, harder alloys, and high-cycle production runs where high-speed steel tooling falls short. It is typically installed by machinists, tool-and-die workers, and maintenance technicians working to ASME B94.11M standards.

Key Features

• Letter D size (0.2460 inches) with diameter tolerance of +0.0000 to -0.0007 inches
• M42 cobalt construction for heat resistance in heavy-duty cutting applications
• 135-degree split point reduces thrust and self-centers on entry
• Parabolic flute profile with web thinning for improved chip flow and reduced torque
• Screw machine (stub) length at 2.5 inches overall provides rigidity in tight setups
• Right-hand cut, straight-cylindrical shank compatible with standard chucks and collets

Compatibility

Designed as an OEM-style replacement and standard production tooling option for drill presses, CNC machining centers, and turret lathes accepting a 0.2460-inch straight-cylindrical shank bit in the screw machine length format. Primary workpiece materials include alloy steel and aluminum per supplier specification.

Installation Notes

A licensed machinist or qualified technician should ensure the machine spindle is fully stopped and the chuck is secure before seating or removing the bit. Verify chuck or collet capacity matches the 0.2460-inch shank diameter before tightening. Use appropriate cutting fluid for the workpiece material to extend tool life and maintain dimensional accuracy. Follow ASME B94.11M guidelines for drill bit handling and storage to prevent edge damage.