Hertel K007312AS Spiral Flute Sti Tap 8-32 Unc Hss

Product Description

The HERTEL K007312AS is a spiral flute STI (Screw Thread Insert) tap designed to cut internal threads for Helicoil-style insert installation in 8-32 UNC applications. Manufactured from high-speed steel with a bright finish, this tap features three flutes, a 52-degree helix angle, and a bottoming chamfer that allows threading close to the base of blind holes. At 2.375 inches overall length, it is sized for bench work and machine tapping in production and repair environments. Licensed machinists, tool and die makers, and maintenance technicians use this tap when preparing stripped or damaged thread bores for thread insert repair.

This tap is used in applications requiring STI thread profiles that accept Helicoil or equivalent wire thread inserts. The bottoming chamfer makes it appropriate for shallow blind holes where full thread engagement close to the bottom is required. Typical install scenarios include aerospace, automotive, and general manufacturing repair work where base material threads have failed and insert-based restoration is the specified repair method. It is suited for use in steel, aluminum, cast iron, and similar materials within the capacity of high-speed steel tooling.

Key Features

• 8-32 UNC thread size with STI profile for Helicoil-style insert preparation
• 52-degree helix angle promotes chip ejection in blind-hole tapping
• Bottoming chamfer allows full thread depth close to the base of blind holes
• Three-flute design balances cutting load and chip clearance
• High-speed steel construction provides durability across a range of base materials
• Bright finish for general-purpose tapping without coating-specific coolant requirements

Compatibility

Compatible with Helicoil insert systems; Helicoil reference number 5905-2. Designed as an STI tap for use with 8-32 UNC wire thread inserts following H2 thread limit specifications.

Installation Notes

This tap is installed by qualified machinists or maintenance technicians using a tap wrench, tapping head, or CNC machine with appropriate feed and speed parameters for the base material. Ensure the workpiece is securely fixtured and the bore is drilled to the correct STI tap drill diameter before tapping. Use cutting fluid appropriate for the base material to extend tool life and improve thread finish. Do not back-tap a bottoming tap into a blind hole without clearing chips, as packing can break the tap.