Hertel K007002AS Spiral Point Sti Tap 4-40 Unc Hss

Product Description

The HERTEL K007002AS is a spiral point STI tap designed for cutting Screw Thread Insert (STI) threads in a 4-40 UNC configuration. It features a plug chamfer for starting taps in through-hole applications and is manufactured from high-speed steel (HSS) with a bright, uncoated finish. The overall length is 2 inches, with a thread length of 11/16 inches and a 2-flute design that drives chips forward ahead of the cut. This tap is suited for machinists, maintenance technicians, and metalworking professionals who need to prepare tapped holes to accept helical insert hardware such as Helicoil-style inserts.

This tap is used in metalworking and maintenance applications where standard tapped threads have been stripped or where added thread strength is required. The STI thread form overcuts the hole to the correct diameter so a helical coil insert can be installed, effectively restoring or reinforcing the thread. It is appropriate for use in aluminum, mild steel, and other materials commonly found in light manufacturing, MRO, and field repair scenarios. The plug chamfer makes it suitable for through-hole passes where chip clearance is not a concern.

Key Features

• STI thread form sized for 4-40 UNC helical insert installation
• Plug chamfer for through-hole tapping applications
• 2-flute spiral point design pushes chips forward ahead of the cutting edge
• High-speed steel construction provides wear resistance across a range of materials
• Bright, uncoated finish suitable for use with standard cutting fluids
• H1 thread limit for close-tolerance thread production

Compatibility

Compatible with Helicoil-style screw thread inserts for 4-40 UNC threads. Helicoil reference number 04CSB is noted in manufacturer specifications. Designed as an OEM-style replacement or direct-use tap for applications requiring STI UNC thread preparation prior to helical insert installation.

Installation Notes

This tap should be installed and operated by qualified machinists or maintenance technicians familiar with thread cutting procedures. Always secure the workpiece properly and use an appropriate cutting fluid for the base material being tapped. Apply consistent, controlled torque and back off periodically to clear chips and prevent tap breakage. Follow applicable workplace safety standards and tool manufacturer guidelines when operating tapping equipment.