Heli-coil 8CPB Hand Sti Tap 1/2-13 Unc H3 Plug Chamfer

Product Description

The HELI-COIL 8CPB is a hand STI tap designed to cut threads sized for wire thread insert installation in 1/2-13 UNC applications. Built from high-speed steel with a bright uncoated finish, it features 4 flutes and a plug chamfer for starting in through-holes or deep blind holes with adequate clearance. The H3 thread limit and 3B class of fit ensure the resulting threads accept standard helical coil inserts with proper tolerance. Overall length is 3-13/16 inches with a thread length of 1-13/16 inches. Licensed machinists, maintenance technicians, and tool-and-die professionals use this tap when repairing stripped or damaged threads in metal components.

The 8CPB is used in thread repair applications across industrial maintenance, aerospace, automotive, and general manufacturing environments. It is applied wherever a standard thread needs to be restored to accept a HELI-COIL wire insert, effectively bringing the repaired fastener bore back to original specification. The plug chamfer makes it suitable for through-hole and deeper blind-hole configurations where there is sufficient thread runout. It is driven by hand using a tap wrench, making it practical for field service, bench repair, and production rework operations.

Key Features

• STI thread form sized for HELI-COIL wire insert installation in 1/2-13 UNC thread repairs
• H3 thread limit with 3B class of fit for consistent insert-ready thread tolerance
• 4-flute geometry for balanced cutting and chip clearance in metallic workpieces
• Plug chamfer allows starting in through-holes and blind holes with adequate depth
• High-speed steel construction provides durability across ferrous and non-ferrous materials
• Bright uncoated finish with no additional coating to affect dimensional accuracy

Compatibility

Designed for use with HELI-COIL wire thread inserts in 1/2-13 UNC thread repair applications. Accepts a standard tap wrench via the square drive shank.

Installation Notes

This tap is operated by hand using a tap wrench - power driving is not recommended and may result in tap breakage or out-of-tolerance threads. Ensure the workpiece is secured and the bore is center-drilled to the correct STI tap drill size before tapping. Apply cutting fluid appropriate to the workpiece material throughout the operation. Follow the insert manufacturer guidelines for insert installation after tapping is complete.