Heli-coil 04CPA Hand Sti Tap 4-40 Unc H2 Plug Chamfer

Product Description

The HELI-COIL 04CPA is a hand STI (Screw Thread Insert) tap designed to cut threads in parent material to accept helical coil thread inserts. It produces a 4-40 UNC thread profile to the H2 thread limit, holding close tolerances required for reliable insert seating. The three-flute plug chamfer design provides balanced cutting action and a gradual lead-in, making it well suited for through-hole and moderately deep blind-hole tapping operations. Manufactured from high speed steel with a bright finish, the 04CPA delivers consistent performance in ferrous and non-ferrous base materials. Licensed machinists, maintenance technicians, and field service professionals use this tap when repairing stripped or damaged 4-40 threads.

This tap is used wherever a helical coil thread insert must be installed in a 4-40 UNC tapped hole. Typical applications include stripped thread repair in thin-walled aluminum housings, electronic enclosures, instrumentation panels, and light mechanical assemblies. The H2 thread limit and Class 2B fit standard make it appropriate for general-purpose commercial thread repair and insert installation work across light industrial, HVAC equipment, and electrical panel applications.

Key Features

• 4-40 UNC thread profile cut to H2 thread limit for precise insert fitment
• Three-flute geometry provides balanced cutting and efficient chip clearance
• Plug chamfer offers gradual thread engagement, suitable for through holes and moderate blind holes
• High speed steel construction resists heat and wear across a broad range of base materials
• Bright finish minimizes surface friction during the tapping operation
• Class 2B fit standard supports general-purpose commercial thread insert installations

Compatibility

Designed for use with helical coil thread insert systems requiring a 4-40 UNC STI-tapped hole to Class 2B fit. Consult your thread insert system documentation to confirm tap size and thread limit requirements before use.

Installation Notes

This tap is installed by hand using a standard tap wrench; power tapping is not recommended for STI taps of this size without appropriate torque control. Ensure the workpiece is securely fixtured and the tap is started square to the hole to avoid thread misalignment or breakage. Apply a suitable cutting fluid appropriate to the base material to extend tap life and improve thread quality. Disconnect or de-energize any assembly before performing thread repair work on installed equipment.