Hertel 18766 Countersink 3/8 in 100 Deg 4 Flute Hss

Product Description

The HERTEL 18766 is a single-piece countersink designed for creating clean, chamfered seat profiles in metal and other materials prior to fastener installation. Built from high speed steel (HSS), it features a 3/8 inch head diameter and a 100-degree included angle, making it suited for standard flat-head fastener applications. The four-flute design promotes smooth cutting action and reduces chatter during use. The straight-cylindrical shank measures 3/8 inch in diameter, allowing it to seat securely in standard drill chucks and collet holders used in machine shops, fabrication environments, and field drilling operations.

This countersink is appropriate for use in machining and metalworking applications where precision chamfering is required ahead of flat-head screw or bolt installation. It is commonly used by machinists, pipefitters, and fabricators working on structural steel, plate stock, and similar materials. The 100-degree included angle is a common standard for aerospace and general industrial fastener seating, and the HSS construction holds up under repeated use in both manual drill press and CNC setups at appropriate feed and speed rates.

Key Features

• 3/8 inch head diameter suits standard flat-head fastener countersink profiles
• 100-degree included angle matches common industrial and structural fastener seat specifications
• Four-flute geometry reduces chatter and produces a cleaner finish than single-flute designs
• High speed steel construction provides hardness and wear resistance for metal cutting applications
• Straight-cylindrical 3/8 inch shank fits standard drill chucks and collet holders

Compatibility

Designed as an OEM-style single-piece countersink compatible with standard 3/8 inch straight-shank drill chucks and collet holders used in bench drill presses, mill spindles, and hand-held drilling equipment.

Installation Notes

A licensed machinist or qualified tradesperson should set appropriate spindle speed and feed rate for the workpiece material before use. Secure the workpiece firmly before engaging the tool to prevent movement and ensure a clean seat profile. Always wear appropriate eye protection and follow applicable shop safety standards when operating rotary cutting tools. Inspect the cutting edges for wear or chipping before each use and replace the tool if damage is observed.