Chicago-latrobe 41790 Jobber Drill Bit Letter T Hss Tin

Product Description

The CHICAGO-LATROBE 41790 is a jobber-length twist drill bit sized to Letter T (0.3580 inches) and designed for heavy-duty drilling applications in metal. Built from high-speed steel with a titanium nitride (TiN) coating, the bit delivers extended wear life and improved chip evacuation compared to uncoated HSS tooling. The 135-degree split point reduces walking on entry and lowers thrust requirements, making it well suited for production drilling and field service work. Overall length is 4-7/8 inches, flute length is 3-1/2 inches, and the straight-cylindrical shank measures 1.375 inches. The web-thinned, tapered web construction supports consistent performance on harder workpiece materials.

This bit is intended for drilling cast iron, stainless steel, and carbon steel in both shop and field environments. The right-hand spiral flute geometry and regular spiral type are suited to general-purpose metal drilling where a standard jobber length provides adequate reach without sacrificing rigidity. It is a single-piece, individually packaged bit appropriate for use in hand drills, drill presses, and CNC drilling equipment where a straight-cylindrical shank is accepted. The Series 150ASP-TN designation places it in CHICAGO-LATROBE's high-performance heavy-duty product line, built to NAS 907 Type B standards.

Key Features

• Letter T sizing at 0.3580 inches decimal equivalent with a diameter tolerance of -0.0010 to 0.0000 inches
• 135-degree split point reduces thrust and prevents bit walking on entry
• Titanium nitride (TiN) coating increases surface hardness and extends tool life on ferrous metals
• Web-thinned tapered web improves chip clearance during deeper cuts
• Right-hand cut, 2-flute regular spiral geometry compatible with standard drill equipment
• Meets NAS 907 Type B specification for heavy-duty drilling applications

Compatibility

Designed for drilling cast iron, stainless steel, and carbon steel. Fits any drill press, hand drill, or CNC spindle that accepts a straight-cylindrical shank at the Letter T diameter. Compatible with coolant-free setups; this bit does not support coolant-through delivery.

Installation Notes

Secure the bit fully in the chuck before operation and verify the shank is seated without runout. Use appropriate cutting fluid or oil when drilling stainless steel or hardened materials to reduce heat buildup and extend tool life. Operate at speeds and feeds appropriate for the workpiece material and bit diameter per standard machining references. Inspect the cutting edges before each use and replace the bit if chipping or wear is visible at the split point.