Hertel 18259 Countersink 1/4 in 82 Degree 1 Flute Hss

Product Description

The HERTEL 18259 is a single-flute countersink designed for producing clean, accurately angled seat profiles in metal and other hard materials. Built from high speed steel, this tool delivers consistent cutting performance across production and maintenance applications. The 82-degree included angle is the standard for flat-head fastener seating in North American applications. With a 0.25-inch head diameter and matching 0.25-inch straight cylindrical shank, the 18259 fits standard drill chucks and collet holders without adapters. It is suited for machinists, maintenance technicians, and fabricators working with hand drills, drill presses, and CNC equipment.

This countersink is used wherever a flush or sub-flush flat-head screw seat is required. Common applications include sheet metal fabrication, light structural work, and general machine shop operations. The single-flute design reduces chatter on handheld operations and is effective in materials such as aluminum, mild steel, and plastics. Its compact head diameter makes it practical for close-tolerance work where larger countersinks would interfere with adjacent features.

Key Features

• 82-degree included angle matches standard flat-head fastener geometry
• Single-flute design minimizes chatter during handheld drilling operations
• High speed steel construction provides durability across metal and plastic substrates
• 0.25-inch head diameter suits tight-clearance countersinking tasks
• Straight cylindrical shank is compatible with standard drill chucks and collets

Compatibility

Designed as a standard single-flute countersink for use in drill presses, hand drills, and CNC spindles accepting a 0.25-inch straight cylindrical shank.

Installation Notes

This tool is installed by a machinist or maintenance technician in any drill chuck or collet rated for a 0.25-inch straight shank. Secure the workpiece before operation and confirm the drill press or machine is powered down before tooling changes. Use appropriate cutting fluid when countersinking steel to extend tool life and maintain finish quality. Follow shop safety standards and applicable machine guarding requirements during operation.