Heli-coil A1191-10CN625 Free Running Insert 5/8-18 Unf

Product Description

The HELI-COIL A1191-10CN625 is a free running threaded insert designed to restore or reinforce internal threads in worn, stripped, or damaged parent material. The insert installs into a prepared tapped hole and provides a durable stainless steel thread form that meets the original design load requirements. At 0.625 inches overall length with a 1D length-to-diameter ratio, this insert fits a 5/8-18 UNF thread application. It features a tanged design for installation with a standard HELI-COIL drive tool. Machinists, maintenance technicians, and assembly professionals use these inserts across industrial, automotive, and mechanical service work.

This insert is suited for applications requiring thread repair or thread strengthening in aluminum, cast iron, magnesium, plastics, or other materials that cannot reliably hold a standard fastener thread over repeated use cycles. The 5/8-18 UNF thread size is common in precision fastener assemblies, automotive components, and industrial machinery where fine-thread engagement is specified. The bright, uncoated finish makes this insert appropriate for environments where surface treatments are not required or where post-installation coating will be applied by the installer.

Key Features

• 5/8-18 UNF thread size for fine-thread applications
• 0.625 inches overall length with 1D length-to-diameter ratio
• 304 stainless steel construction for corrosion resistance and strength
• Tanged design for use with standard HELI-COIL installation tooling
• Bright, uncoated finish - 9 free coils per insert
• Single insert per package

Compatibility

Designed as an OEM-style thread repair insert for 5/8-18 UNF tapped holes in applications requiring a free running insert with 1D engagement length.

Installation Notes

Installation requires a properly sized HELI-COIL tap and the appropriate drive tool for the insert diameter - do not attempt to install with improvised tooling. The parent material must be drilled and tapped to the correct HELI-COIL oversize specification before the insert is driven in. After installation, the tang is broken off using a tang break-off tool or needle-nose pliers. Always de-energize or lock out any equipment before performing thread repair on mechanical assemblies.