Hertel K007330AS Spiral Flute Sti Tap 5/16-18 Unc Hss

Product Description

The HERTEL K007330AS is a spiral flute STI (Screw Thread Insert) tap designed for cutting internal threads that accept Helicoil-style inserts in ferrous and non-ferrous workpieces. Built from high speed steel with a bright finish, this tap features a 52-degree helix angle that promotes efficient chip evacuation up and out of the hole — a geometry well suited for through-hole and blind-hole applications in softer materials. The bottoming chamfer allows threading close to the bottom of a blind hole, maximizing thread engagement depth. With a thread size of 5/16-18 UNC and an H4 thread limit, it produces oversized threads dimensioned specifically for insert installation.

This tap is used in maintenance, repair, and manufacturing environments where stripped or damaged threads are being reconditioned using Helicoil-style inserts. It is appropriate for use on aluminum, mild steel, cast iron, and similar machinable materials. The Helicoil reference number for this tap is 6905-5, making it straightforward to match with the correct insert kit. It is typically used by machinists, tool and die technicians, and maintenance professionals working on threaded fastener repair or original equipment assembly.

Key Features

• 5/16-18 UNC thread size with H4 thread limit for proper STI insert fit
• 52-degree helix angle promotes upward chip evacuation in blind holes
• Bottoming chamfer allows threading to near the base of a blind hole
• Three-flute design provides rigidity and consistent thread form
• High speed steel construction handles a broad range of machinable materials
• Bright finish with no coating — suitable for use with cutting fluid or tapping compound

Compatibility

Corresponds to Helicoil reference number 6905-5. Designed for use with 5/16-18 UNC Helicoil-style screw thread inserts in standard STI tapping applications.

Installation Notes

Installation is performed by machinists or maintenance technicians using a standard tap wrench, tapping head, or CNC tapping cycle with appropriate feed rate and spindle speed for the workpiece material. Power down any machine tool and secure the workpiece firmly before beginning. Use a quality tapping compound or cutting fluid to extend tap life and improve thread finish. Follow the insert manufacturer's instructions for drill size and insert installation after tapping is complete.