Chicago-latrobe 54124 Cobalt Drill Bit Letter Y 0.4040 in

Product Description

The CHICAGO-LATROBE 54124 is a cobalt jobber length drill bit sized to Letter Y (0.4040 inches) and built for demanding metalworking applications. The bit features a 135-degree split point that self-centers on contact, reducing walking and the need for a center punch. A titanium nitride (TiN) coating increases surface hardness and extends tool life in abrasive materials. The two-flute spiral design with a regular helix promotes efficient chip evacuation. At 5.25 inches overall length with a 3.875-inch flute length, it fits standard drill chucks and drill presses used in fabrication, MRO, and maintenance work. This is a heavy-duty, high-performance tool built to M42 cobalt high-speed steel standards.

The 54124 is designed for drilling stainless steel and steel, including difficult-to-machine alloys where standard HSS bits lose edge quickly. The TiN coating and M42 cobalt substrate handle the heat generated in stainless steel applications. A straight cylindrical shank with a 0.4040-inch diameter seats cleanly in keyed or keyless chucks. Typical install scenarios include structural fabrication shops, pipe fitting, and maintenance crews working on stainless fastener holes or precision-clearance bores. Conforms to DIN 338 and NAS 907 Type J standards.

Key Features

• Letter Y size, 0.4040 inches decimal equivalent, with diameter tolerance of -0.0010 to 0.0000 inches
• 135-degree split point with web thinning for self-centering starts and reduced thrust
• M42 cobalt high-speed steel construction for heat resistance in stainless steel and alloy steel
• Titanium nitride (TiN) coating extends surface hardness and tool life
• Tapered web configuration with regular spiral flute for controlled chip evacuation
• Meets DIN 338 and NAS 907 Type J standards; Series 2550 heavy-duty grade

Compatibility

Designed as an OEM-style replacement or direct-use drill bit for applications requiring a Letter Y (0.4040-inch) jobber length bit in stainless steel and steel. Compatible with standard straight-shank drill chucks on hand drills, drill presses, and CNC drilling equipment.

Installation Notes

This bit is installed by machinists, fabricators, and maintenance technicians using standard keyed or keyless drill chucks. Secure the straight cylindrical shank fully in the chuck before operation and verify runout is within acceptable limits. Use appropriate cutting fluid or coolant when drilling stainless steel to manage heat buildup and extend tool life. Replace the bit if point geometry is visibly degraded, as a dull split point on stainless steel increases heat and work hardening risk.