Hertel K007074AS Spiral Point Sti Tap 3/8-16 Unc

Product Description

The HERTEL K007074AS is a spiral point STI tap designed for cutting Screw Thread Insert (STI) threads in a range of metals and alloys. It features a 3/8-16 UNC thread form with a plug chamfer, making it suitable for through-hole tapping applications where the tap is driven straight through the workpiece. Manufactured from high-speed steel (HSS) with a bright/uncoated finish, this tap offers good wear resistance for general-purpose production and maintenance tapping. The spiral point geometry pushes chips forward ahead of the cutting flutes, reducing chip clogging in through-hole applications. Overall length is 3.375 inches. Licensed machinists, toolmakers, and maintenance technicians are the typical users.

This tap is used wherever a Screw Thread Insert requires a properly sized pilot thread, most commonly in aerospace, automotive, and general manufacturing maintenance when restoring or upsizing stripped or damaged threads. The 3/8-16 UNC thread size is one of the most common coarse-pitch fastener sizes in North American industry. With three flutes and a plug chamfer, the K007074AS is suited to through-hole tapping in steel, cast iron, aluminum, and similar machinable materials on manual machines, drill presses, or CNC tapping centers running appropriate tap speeds and lubricants.

Key Features

• Thread form: 3/8-16 UNC STI (Screw Thread Insert) for use with standard helicoil-style inserts
• Plug chamfer (7-10 threads) for through-hole tapping applications
• 3-flute spiral point geometry pushes chips forward, reducing clogging in through-holes
• High-speed steel construction provides toughness for general-purpose tapping
• Bright/uncoated finish suitable for use with cutting oil or water-soluble coolants
• H3 thread limit for controlled fit with standard STI insert tolerances

Compatibility

Designed as an OEM-style STI tap for use with standard 3/8-16 UNC screw thread inserts. Helicoil reference number 6CSB is noted in product specifications.

Installation Notes

Tapping operations should be performed by a qualified machinist or maintenance technician familiar with thread insert installation procedures. Always ensure the workpiece is securely fixtured and the tap is properly aligned before engaging the cut. Apply an appropriate cutting fluid for the workpiece material to extend tap life and improve thread quality. Back the tap out periodically to clear chips and prevent tap breakage, even with spiral point geometry in deeper applications.