Hertel 18509 Countersink 1/4 in 120 Degree 6 Flute Hss

Product Description

The HERTEL 18509 is a high speed steel countersink designed for creating clean, angled seat profiles in metal and other materials prior to fastener installation. It features a 1/4 inch head diameter, a 120 degree included angle, and six flutes that distribute cutting load and improve chip evacuation. The straight cylindrical shank measures 1/4 inch in diameter for direct chuck mounting. This tool is used by machinists, maintenance technicians, pipefitters, and fabricators working on sheet metal, structural components, and pipe flange preparation where precise countersunk fastener seating is required.

The 18509 is suited for light to medium countersinking operations on ferrous and non-ferrous metals. The 120 degree included angle accommodates fastener head geometries common in industrial and mechanical assembly applications. The six-flute configuration provides a smoother finish on the countersunk seat compared to lower-flute-count tools, making it appropriate for applications where surface quality at the fastener bearing face matters. It is typically installed in a drill press, CNC machine, or handheld drill with a standard chuck capable of accepting a 1/4 inch straight shank.

Key Features

• 1/4 inch head diameter for small-diameter countersink applications
• 120 degree included angle for industrial fastener seat preparation
• Six flutes for improved chip evacuation and smoother seat finish
• High speed steel construction provides durability across metal cutting tasks
• 1/4 inch straight cylindrical shank for standard chuck compatibility

Compatibility

Designed as a direct-fit countersink for use in any drill press, CNC spindle, or handheld drill accepting a 1/4 inch straight cylindrical shank; compatible with standard 3-jaw and collet chuck systems.

Installation Notes

Installation and use should be performed by qualified machinists or tradespeople familiar with rotary cutting tool safety. Secure the shank fully in the chuck before operating and verify chuck is tightened to prevent tool walkout. Wear appropriate eye protection and secure the workpiece before beginning any cutting operation. Refer to applicable shop safety standards and tool manufacturer speed recommendations for the material being cut.