Hertel 18021 Countersink 1/2 in 82 Degree 1 Flute Hss

Product Description

The HERTEL 18021 is a single-flute high speed steel countersink designed to produce clean, accurately angled seats in metal, wood, and composite materials. With a 1/2 inch head diameter and an 82-degree included angle, this tool creates the precise conical recesses required for flat-head fasteners to sit flush with or below a workpiece surface. The straight cylindrical shank measures 3/8 inch in diameter, fitting standard drill chucks and collet holders found in most machine shop and production environments. Machinists, tool and die technicians, and fabricators rely on this style of countersink for consistent, repeatable results in drilling and finishing operations.

The 18021 is suited for light to medium countersinking tasks across a range of materials including mild steel, aluminum, and plastics. Its single-flute geometry reduces chatter and produces a smoother finish compared to multi-flute designs, making it a practical choice for applications where surface quality at the fastener seat is critical. It is commonly used in sheet metal fabrication, general machining, and maintenance repair operations requiring standard 82-degree flat-head screw clearance.

Key Features

• 82-degree included angle matches standard flat-head fastener specifications
• 1/2 inch head diameter provides adequate coverage for common screw sizes
• Single-flute design minimizes chatter and improves surface finish quality
• High speed steel construction offers good wear resistance across a range of workpiece materials
• 3/8 inch straight cylindrical shank fits standard drill chucks and collet holders

Compatibility

Designed as a standard single-flute countersink for use in drill presses, milling machines, and handheld drill applications requiring a 3/8 inch straight shank and 82-degree seating angle.

Installation Notes

This countersink is installed by a machinist or fabricator into a compatible chuck or collet holding a 3/8 inch straight shank. Secure the shank fully and verify runout before beginning operation. Use appropriate cutting fluid or lubricant when countersinking steel to extend tool life and improve finish. Always power down the machine and confirm the spindle has stopped completely before changing or inspecting tooling.