Heli-coil R1191-5 Free Running Insert 5/16-24 Unf

Product Description

The HELI-COIL R1191-5 is a free running wire thread insert designed to create strong, wear-resistant internal threads in parent materials where thread repair or reinforcement is required. Sized for 5/16-24 UNF threads with an overall length of 0.469 inches, this tanged insert is manufactured from stainless steel with a bright, uncoated finish. It installs into a pre-drilled and tapped hole using a standard HELI-COIL installation tool. Each package contains 12 inserts. The 1-1/2D length-to-diameter ratio provides a solid thread engagement suitable for general fastening applications in metalworking and mechanical assembly.

Free running inserts are used where a smooth, low-friction thread fit is needed and no locking or prevailing torque is required. This insert is appropriate for thread repair in aluminum, cast iron, magnesium, and other materials prone to thread stripping, as well as for original equipment manufacturing where a hardened thread form is specified. Applications span aerospace, automotive, HVAC equipment assembly, and industrial machinery maintenance. The tanged design requires a tang break-off tool after installation in blind holes.

Key Features

• 5/16-24 UNF thread size for fine-pitch fastening applications
• 0.469 inches overall length with a 1-1/2D length-to-diameter ratio
• Tanged design for positive drive during installation
• Stainless steel construction for corrosion resistance
• Bright, uncoated finish with 8-7/8 free coils
• Sold in packages of 12 inserts

Compatibility

Designed as an OEM-style thread insert for use in any parent material tapped to the HELI-COIL R1191 series specification for 5/16-24 UNF free running inserts.

Installation Notes

Installation requires a properly sized HELI-COIL tap and a matching installation tool for the 5/16-24 UNF insert series. Always de-energize and depressurize any system before performing thread repair on component housings. In blind holes, a tang break-off tool must be used to remove the drive tang after the insert is seated. Follow the equipment manufacturer service documentation and applicable codes for thread repair procedures.