Hertel 19203 Countersink 5/16 in 90 Degree 1 Flute Hss

Product Description

The HERTEL 19203 is a single-flute countersink designed for creating conical seat profiles in metal, plastic, and composite materials. With a 5/16-inch head diameter and a 90-degree included angle, it cuts the tapered recess required for flat-head fasteners to sit flush with a workpiece surface. The straight cylindrical shank measures 1/4 inch in diameter, making it compatible with standard drill chucks and quick-change holders. The body is manufactured from high speed steel, providing heat resistance and edge retention across a range of common workpiece materials. This tool is used by machinists, fabricators, maintenance technicians, and skilled tradespeople working on sheet metal, structural components, and assemblies.

The 19203 is suited for light-duty countersinking operations in shop and field environments. The single-flute geometry produces a clean, chatter-reduced cut, which is especially useful when working with softer metals and plastics where multi-flute tools can grab or vibrate. The 1/4-inch straight shank seats directly in standard drill press chucks, handheld drill drivers, or milling machine collets. It is a practical choice for maintenance and repair work, custom fabrication, and any application requiring consistent 90-degree countersunk fastener seats.

Key Features

• 5/16-inch head diameter produces a properly sized countersink for common flat-head fastener sizes
• 90-degree included angle matches the most widely used flat-head screw and rivet seat geometry
• Single-flute design reduces chatter and grabbing in softer workpiece materials
• High speed steel construction provides heat and wear resistance for general-purpose cutting
• 1/4-inch straight cylindrical shank fits standard drill chucks and quick-change systems without adapters

Compatibility

Designed as a general-purpose countersink for use with standard 1/4-inch drill chucks, drill press spindles, and collet-style quick-change holders commonly found in shop and field environments.

Installation Notes

A qualified machinist or tradesperson should secure the workpiece firmly before operation to prevent movement during cutting. Set drill speed appropriate to the workpiece material — lower speeds for harder metals, higher speeds for plastics and soft alloys — and apply cutting fluid when working with ferrous metals to extend tool life. Inspect the cutting edge before use and do not force the tool into the material; light, steady feed pressure produces the cleanest seat geometry.