Hertel 18751 Countersink 5/16 in 90 Degree 4 Flute Hss

Product Description

The HERTEL 18751 is a straight-shank countersink designed for creating clean, chamfered seat profiles in metal, plastic, and composite materials. Built from high-speed steel, this tool offers reliable wear resistance in general-purpose drilling and countersinking operations. The 90-degree included angle suits standard fastener seating requirements across a wide range of applications. With a 5/16-inch head diameter and a matching 5/16-inch straight cylindrical shank, it fits securely in standard drill chucks and collet holders. The four-flute configuration improves cutting efficiency and helps reduce chatter during operation, making it a dependable choice for machinists and fabricators working on precision assemblies.

The HERTEL 18751 is suited for use in machine shops, fabrication facilities, and maintenance environments where consistent countersink geometry is required. It is typically used to prepare holes for flat-head screws, rivets, and similar flush-mount fasteners in ferrous and non-ferrous workpieces. The straight cylindrical shank allows straightforward mounting in standard drill press, lathe, or hand-drill setups. This tool is appropriate for both production runs and one-off maintenance tasks where a reliable, correctly-angled seat is needed.

Key Features

• 5/16-inch head diameter for compact countersink profiles
• 90-degree included angle matches standard flat-head fastener geometry
• Four-flute design improves cutting action and reduces chatter
• High-speed steel construction provides good wear resistance in general-purpose applications
• Straight cylindrical shank fits standard drill chucks and collet systems without adapters

Compatibility

Designed as a general-purpose countersink for use in standard drill presses, lathes, and hand-drill setups where a 5/16-inch straight cylindrical shank is accepted.

Installation Notes

Secure the shank firmly in a drill chuck or collet before operation and confirm runout is within acceptable limits. Apply cutting fluid when working with ferrous metals to extend tool life and improve finish quality. Use appropriate machine guarding and eye protection in accordance with applicable shop safety standards. Inspect the cutting edges before each use and remove the tool from service if chipping or excessive wear is observed.