Heli-coil A1191-12CN1125 Free Running Insert 3/4-16

Product Description

The HELI-COIL A1191-12CN1125 is a free running wire thread insert designed to restore or reinforce internal threads in tapped holes. Made from 304 stainless steel with a bright, uncoated finish, this insert installs into a pre-drilled and tapped hole to create a durable, corrosion-resistant threaded engagement. The insert accepts a 3/4-16 UNF fastener and measures 1.125 inches overall in length, yielding a 1-1/2D length-to-diameter ratio. It features a tang for installation and is suited for applications where thread strength and material integrity are critical. Technicians in HVAC, plumbing, and mechanical service use inserts like this to repair stripped threads in aluminum, cast iron, and similar base materials.

This insert is intended for use in threaded repair applications requiring a 3/4-16 UNF thread form. The 1-1/2D length provides solid thread engagement suitable for general mechanical and structural fastening scenarios. With 15-1/8 free coils and a tanged design, it is compatible with standard HELI-COIL installation tooling. The bright, uncoated 304 stainless steel construction makes it appropriate for environments where mild corrosion resistance is needed without additional surface treatment.

Key Features

• Thread size 3/4-16 UNF for precise fastener fitment
• Overall length of 1.125 inches with a 1-1/2D length-to-diameter ratio
• 304 stainless steel construction for corrosion resistance
• Tanged design for use with standard installation drivers
• 15-1/8 free coils for full thread engagement
• Bright, uncoated finish - no additional surface treatment applied

Compatibility

Designed as an OEM-style thread repair insert for applications requiring a 3/4-16 UNF threaded engagement in metallic base materials.

Installation Notes

Installation requires a correctly sized HELI-COIL tap and the appropriate insertion tool for the 3/4-16 thread size. Ensure the base material hole is drilled and tapped to the specified HELI-COIL tap size before installing the insert. After installation, remove the tang using a tang break-off tool per standard procedure. Follow all applicable mechanical fastening codes and manufacturer installation guidelines.