Heli-coil 5551-6 Thread Insert Tool 3/8-16 Unc

Product Description

The HELI-COIL 5551-6 is a hand installation tool designed to drive threaded wire inserts into pre-tapped holes. It is used to install Stud-Lock thread inserts at the 3/8-16 UNC thread size. The tool engages the insert tang and winds it into the tapped bore with controlled torque applied by hand, seating the insert flush or to the specified depth. HVAC technicians, plumbers, machinists, and general maintenance professionals use this tool when restoring or reinforcing damaged internal threads in metal housings, manifolds, brackets, and equipment casings.

This tool is suited for repair and manufacturing applications where 3/8-16 UNC Stud-Lock inserts are specified. Stud-Lock inserts grip installed studs or fasteners to resist loosening under vibration, making this installation tool relevant in mechanical assemblies, compressor housings, equipment frames, and other components subject to dynamic loads. The hand-drive format makes it practical for field service and shop use where power tools are not needed or not appropriate.

Key Features

• Designed specifically for Stud-Lock thread insert installation at 3/8-16 UNC
• Hand installation tool type - no power tool required
• UNC thread standard ensures compatibility with unified coarse fastener systems
• Lightweight at 0.4 pounds, suitable for tool bag or field kit
• Single-piece quantity with minimum order quantity of one

Compatibility

Compatible with HELI-COIL Stud-Lock thread inserts in the 3/8-16 UNC thread size. Designed as an OEM-style hand installation tool for use within the HELI-COIL insert system for that thread specification.

Installation Notes

This tool is intended for use by machinists, maintenance technicians, and trade professionals familiar with thread insert installation procedures. Before installation, ensure the host material has been drilled and tapped to the correct HELI-COIL tap size for 3/8-16 UNC inserts. Power down or de-energize any equipment before performing thread repair on live assemblies. Do not apply excessive torque during hand installation, as over-driving may damage the insert or the tapped bore.