Hertel K008174AS Straight Flute Tap 6-40 Unf Hss

Product Description

The HERTEL K008174AS is a straight flute tap designed to cut 6-40 UNF internal threads in through-holes and blind holes where chip evacuation is straightforward. Built from high-speed steel with a bright, uncoated finish, it features a plug chamfer for gradual thread engagement and is ground to an H2 thread limit for consistent tolerance control. With 2 straight flutes and a right-hand thread direction, this tap suits machine and hand tapping operations in a 2B or 3B class of fit. Overall length is 2 inches. Machinists and maintenance technicians reach for this tap when threading small-diameter fastener holes in ferrous and non-ferrous materials.

This tap is intended for 6-40 UNF thread applications in production and repair environments. The plug chamfer style makes it appropriate for through-holes and moderately deep blind holes where the chamfer lead can fully engage before reaching the bottom. Common applications include threading holes for instrument screws, small electrical panel hardware, and precision mechanical assemblies. The straight flute geometry works best in materials that produce short, brittle chips rather than long, stringy ones.

Key Features

• 6-40 UNF thread form with right-hand thread direction
• Plug chamfer for gradual thread engagement over several lead threads
• H2 thread limit for tight tolerance and consistent class of fit
• 2B and 3B class of fit compatibility covers standard and close-tolerance applications
• High-speed steel construction provides durability in general-purpose tapping
• Bright, uncoated finish suitable for use with standard cutting fluids

Compatibility

Designed as an OEM-style straight flute tap for 6-40 UNF threaded holes requiring a 2B or 3B class of fit in general machining and maintenance applications.

Installation Notes

This tap should be installed by a qualified machinist or maintenance technician using appropriate tapping fluid or cutting oil for the work material. Always secure the workpiece and align the tap perpendicular to the hole before beginning to prevent thread distortion or tap breakage. Back the tap off periodically to break chips and clear the flutes when working in deeper holes. Do not apply excessive downward force; allow the tap to feed at its natural thread pitch rate.