Chicago-latrobe 42691 Jobber Drill Bit 21 Tialn Hss

Product Description

The CHICAGO-LATROBE 42691 is a jobber length drill bit designed for high-performance drilling in titanium and other demanding workpiece materials. Built from high speed steel with a TiAlN coating, it carries a wire gauge size of 21, which corresponds to 0.1590 inches in decimal. The bit features a 135-degree split point for reduced thrust and improved centering on entry. A spiral, regular-helix flute design and web-thinned, tapered web configuration promote efficient chip evacuation. Straight-cylindrical shank and a 3.5-inch overall length make it compatible with standard drill chucks across a range of production and maintenance applications. This bit meets NAS 907 Type B standards and is graded for heavy-duty use.

The 42691 is suited for drilling titanium, high-temperature alloys, and similarly tough materials in aerospace, MRO, and precision fabrication environments. With a 2-5/16-inch flute length and a 1.125-inch shank diameter, it fits production setups where consistent hole quality and tool life are priorities. The TiAlN coating provides thermal resistance that extends tool life when cutting speeds and feed rates push into elevated temperature ranges. This bit is sold individually and is appropriate for use in upright drill presses, CNC machining centers, or hand-held pneumatic and electric drills where the chuck capacity accommodates the shank diameter.

Key Features

• Wire size 21 (0.1590 inches) with diameter tolerance of -0.0007 to 0.0000 inches for consistent hole sizing
• 135-degree split point reduces axial thrust and improves self-centering on entry
• TiAlN coating provides thermal resistance and extends tool life in titanium and hard alloy applications
• Web-thinned tapered web reduces cutting resistance and improves chip clearance
• Meets NAS 907 Type B specification for aerospace and precision manufacturing use
• Right-hand cut, regular spiral flute, straight-cylindrical shank for broad chuck compatibility

Compatibility

Designed as an OEM-style replacement or direct-use jobber length drill bit for applications requiring a wire gauge size 21 bit with a straight-cylindrical shank. Compatible with standard drill chucks accepting a 1.125-inch shank diameter. Intended primary workpiece material is titanium per Series 150ASP-TA specifications.

Installation Notes

Installation and use of this drill bit should be performed by machinists or qualified trade personnel familiar with cutting tool setup and safe machine operation. Before mounting, ensure the drill press, CNC spindle, or handheld tool is fully powered down and secured. Confirm chuck capacity is rated for the 1.125-inch shank diameter before tightening. Do not exceed the tool's rated cutting parameters for the workpiece material, and use appropriate cutting fluid or coolant practices even though this bit does not feature through-coolant capability.