Heli-coil 02CPB Hand Sti Tap 2-56 Unc H1 Plug Chamfer

Product Description

The HELI-COIL 02CPB is a hand STI tap designed to cut threads for Screw Thread Insert installation in 2-56 UNC tapped holes. STI taps cut an oversized thread profile that accepts a helical wire insert, restoring or creating a stronger threaded connection than a standard tap would produce. This tap features a plug chamfer for starting in through-holes or moderately deep blind holes, three flutes for chip clearance, and an H1 thread limit for close-tolerance work. The body is ground from high-speed steel with a bright, uncoated finish. It is used by machinists, maintenance technicians, and field service professionals who install thread repair inserts in metal components.

This tap is suited for hand tapping operations in 2-56 UNC thread repair and new-thread applications across light manufacturing, aerospace maintenance, electronics assembly, and general industrial repair. The plug chamfer style makes it a practical choice when threading through-holes or starting in open-ended bores. The H1 tolerance class is appropriate for achieving a 3B class of fit, which covers the standard commercial thread tolerance range for most insert installations. It is sized for use with 2-56 HELI-COIL style inserts and compatible STI tooling.

Key Features

• STI thread profile cuts oversized hole for helical wire insert installation
• 2-56 UNC thread size with H1 thread limit for 3B class of fit
• Plug chamfer allows easy starting in through-holes and open bores
• 3-flute geometry provides chip clearance during hand tapping
• High-speed steel construction for durability across steel, aluminum, and similar materials
• Bright uncoated finish - no coating to affect thread tolerance or dimensional accuracy

Compatibility

Designed for use with 2-56 UNC STI thread insert tooling systems requiring an H1 thread limit tap with plug chamfer. Intended for hand tapping applications where a 3B class of fit is specified.

Installation Notes

This tap is intended for hand tapping only and should be used with a properly sized tap wrench - do not use in a power driver. Ensure the workpiece is securely fixtured before tapping. Apply cutting fluid appropriate for the base material to extend tap life and improve thread quality. Follow the insert manufacturer's drill size chart to confirm the correct STI drill diameter before tapping.