Hertel 86847977 Cobalt Drill Bit No 40 135 Split Point

Product Description

The HERTEL 86847977 is a cobalt threaded shank drill bit designed for drilling into high-tensile strength materials where standard high-speed steel bits fall short. Built to NAS 965 specification, this No. 40 wire gauge bit has a decimal diameter of 0.0980 inches and features a 135-degree split point for fast, self-centering starts without a center punch. The oxide coating improves surface hardness and reduces heat buildup during cutting. The overall length is 2.125 inches with a 0.875-inch flute length. A 1/4-28 threaded shank locks the bit securely in compatible threaded-chuck tooling, preventing slippage under high-torque conditions.

This bit is suited for precision hole drilling in aerospace-grade alloys, stainless steel, hardened steels, titanium, and other high-tensile strength metals. The regular spiral flute geometry and right-hand cutting direction make it a standard choice for production drilling and maintenance applications where consistent, accurate hole sizing in tough materials is required. The tapered web configuration reduces cutting resistance and helps clear chips efficiently during deep drilling passes.

Key Features

• Cobalt construction with oxide coating for drilling high-tensile strength and hardened metals
• 135-degree split point for self-centering entry and reduced thrust force
• 1/4-28 threaded shank for positive engagement in threaded-chuck tooling
• NAS 965 specification compliance for aerospace and precision manufacturing applications
• Web-thinned tapered web reduces cutting resistance and improves chip evacuation
• Right-hand cut, regular spiral flute geometry for standard production drilling

Compatibility

Designed for use in threaded-shank drill chucks or toolholders accepting a 1/4-28 thread interface. Suited for drilling high-tensile strength materials including stainless steel, aerospace alloys, and hardened steels.

Installation Notes

Installation and use should be performed by a qualified machinist or tooling technician familiar with proper drill speeds and feeds for cobalt tooling in hard materials. Ensure the threaded shank is fully engaged and torqued into the holder before operating to prevent bit walk or ejection. Use appropriate cutting fluid or coolant where possible to extend tool life when drilling high-tensile alloys. Always wear appropriate eye protection and follow shop safety protocols when operating rotary cutting tools.