Chicago-latrobe 54058 Cobalt Drill Bit Letter E 1/4 in

Product Description

The CHICAGO-LATROBE 54058 is a cobalt jobber length drill bit in Letter E size, equivalent to 0.2500 inches in diameter. Built to Series 2550 standards and conforming to DIN 338 and NAS 907 Type J specifications, this bit is engineered for high-performance drilling in tough materials including stainless steel and hardened steels. The M42 cobalt construction is paired with a titanium nitride (TiN) coating for extended wear resistance. The 135-degree split point geometry reduces walking and lowers feed pressure at entry, making it well suited for production environments and maintenance shops where precision and tool life matter.

This bit is designed for drilling stainless steel and steel in demanding applications where standard high-speed steel tooling falls short. The regular spiral flute and right-hand cut make it compatible with standard drill presses, CNC machining centers, and hand-held power tools. Machinists, maintenance technicians, pipefitters, and fabricators working in industrial, commercial, and trade settings will find the 54058 appropriate for hole-making tasks where bit longevity and dimensional accuracy are priorities. The tapered web with web thinning further reduces cutting resistance in deep-hole and interrupted-cut scenarios.

Key Features

• M42 cobalt construction for superior heat and wear resistance in hard materials
• TiN coating extends tool life and reduces friction at the cutting edge
• 135-degree split point minimizes walking and reduces required feed force
• Web-thinned, tapered web lowers cutting resistance in deep or interrupted cuts
• Straight-cylindrical shank fits standard 3-jaw chucks without adapters
• Meets DIN 338 and NAS 907 Type J standards for dimensional consistency

Compatibility

Designed as an OEM-style replacement or direct-use jobber length drill bit for applications requiring a Letter E (0.2500 inch) diameter hole in stainless steel or steel workpieces. Fits any standard drill chuck accepting a 1/4 inch straight-cylindrical shank.

Installation Notes

Installation of this bit should be performed by machinists or qualified technicians familiar with proper chuck-mounting procedures and appropriate cutting speeds for cobalt tooling. Secure the shank fully in the chuck before applying power and verify chuck key is removed prior to starting the machine. Use cutting fluid or coolant appropriate for stainless steel when possible to preserve coating and edge life. Do not exceed the recommended surface footage for cobalt M42 tooling in hard materials, as excessive speed generates heat that shortens tool life.