Heli-coil K1191-14 Free Running Insert 7/8-14 Unf

Product Description

The HELI-COIL K1191-14 is a free running helical coil threaded insert designed to create strong, wear-resistant threads in parent materials that require reliable fastener engagement. Manufactured from stainless steel with a bright, uncoated finish, this insert measures 1.312 inches overall length and is sized for 7/8-14 UNF thread applications. The tanged design allows for positive installation using a standard HELI-COIL installation tool, and the 1-1/2D length-to-diameter ratio provides dependable thread engagement depth for high-load fastening applications. Machinists, maintenance technicians, and MRO professionals install this type of insert to repair stripped threads or to build durable tapped holes in softer base materials.

This insert is suited for use in both original equipment manufacturing and field repair applications where a 7/8-14 unified fine thread is required. The free running style allows smooth bolt engagement without locking preload, making it appropriate for assemblies that require frequent disassembly and reassembly. Typical applications include thread repair in aluminum, cast iron, and other metals across industrial, aerospace ground support, and heavy equipment maintenance environments. With 15-1/2 free coils, the insert provides full thread form throughout its installed length.

Key Features

• 7/8-14 UNF thread size for unified fine thread applications
• 1.312 inches overall length at a 1-1/2D length-to-diameter ratio
• Stainless steel construction resists corrosion and galling
• Tanged design for use with standard HELI-COIL installation tooling
• Free running style for smooth, non-locking fastener engagement
• 15-1/2 free coils provide full thread engagement along insert length

Compatibility

Designed as an OEM-style threaded insert replacement for applications requiring a 7/8-14 UNF free running helical coil insert in metallic parent materials.

Installation Notes

Installation requires a matching HELI-COIL tap and installation tool sized for 7/8-14 UNF; the parent hole must be drilled and tapped to the HELI-COIL oversize specification before insert installation. Ensure the parent material is securely fixtured before drilling and tapping operations. After the insert is driven to the correct depth, the installation tang must be broken off using a tang break-off tool. Follow applicable facility safety procedures and wear appropriate eye protection during all thread repair operations.