Chicago-latrobe 41774 Jobber Drill Bit Letter D Tin Hss

Product Description

The CHICAGO-LATROBE 41774 is a jobber-length drill bit sized to Letter D, designed for high-performance drilling in ferrous metals and hard alloys. Built from High Speed Steel (HSS) with a Titanium Nitride (TiN) coating, the bit delivers extended tool life and reduced heat buildup compared to uncoated HSS. The 135-degree split point promotes self-centering and reduces walking on hard surfaces, eliminating the need for a center punch in most setups. Overall length is 4 inches with a flute length of 2.75 inches and a straight cylindrical shank diameter of 0.25 inches. Classified as a heavy-duty grade bit, it meets NAS 907 Type B standards and suits demanding production and maintenance environments.

The 41774 is intended for drilling cast iron, stainless steel, and carbon steel in both shop and field applications. The two-flute spiral configuration evacuates chips efficiently, making it well-suited for through-hole drilling in structural steel, fabrication work, and MRO maintenance tasks. The web-thinned, tapered web design reduces thrust requirements, which is especially beneficial when drilling stainless steel or other work-hardening materials. A licensed machinist, millwright, or experienced tradesperson would typically deploy this bit in a drill press, CNC machine, or heavy-duty hand drill.

Key Features

• Letter D size with 135-degree split point for self-centering and reduced thrust
• TiN coating extends wear resistance and reduces friction during cutting
• High Speed Steel construction rated for cast iron, stainless steel, and carbon steel
• Web-thinned tapered web reduces required feed force on tough materials
• Meets NAS 907 Type B specification for heavy-duty grade performance
• Right-hand spiral flute design promotes efficient chip evacuation

Compatibility

Designed as a jobber-length replacement or production bit compatible with standard 0.25-inch straight-shank drill chucks. Primary workpiece materials are cast iron, stainless steel, and steel per Series 150ASP-TN application data.

Installation Notes

Secure the straight cylindrical shank firmly in a keyed or keyless chuck rated for the shank diameter before use. De-energize and lock out any machine tool before changing bits, per standard lockout/tagout procedures. Apply cutting fluid when drilling stainless steel or other work-hardening alloys to minimize heat buildup and prolong coating life. Avoid excessive feed pressure, which can cause premature point wear or bit breakage in hard materials.