E-z Lok 329-720 Thread Locking Insert 7/16-20 5/8-11 Unf

Product Description

The E-Z LOK 329-720 is a self-locking threaded insert designed to create a secure, vibration-resistant internal thread in existing tapped or drilled holes. It features a 7/16-20 UNF internal thread and a 5/8-11 external thread, with an overall length of 21/32 inches (0.656 inches). Manufactured from C12L14 carbon steel with a smooth, rolled finish, this insert delivers consistent thread engagement in metal parent materials. The self-lock wall design prevents the insert from backing out under dynamic load, making it well-suited for high-vibration assemblies. Licensed trades and manufacturing maintenance technicians install this type of insert when a stripped or undersized thread needs to be restored or reinforced to full load-bearing capacity.

This insert is intended for applications requiring a permanent, locking thread repair or upgrade in carbon steel, cast iron, or similarly machinable parent materials. The 5/8-11 external thread drives into a standard tapped hole, and the 7/16-20 internal thread accepts a corresponding UNF fastener at a 2B class of fit. Typical installations include mechanical assemblies, industrial equipment, and maintenance-repair scenarios where thread integrity under torque and vibration is critical. The standard tap type compatibility means no special tooling is required beyond a conventional 5/8-11 tap.

Key Features

• Self-lock wall design resists backing out under vibration and dynamic loading
• 7/16-20 UNF internal thread (Class 2B fit) accepts standard UNF fasteners
• 5/8-11 external thread (Class 2A fit) installs with a standard tap - no special tooling required
• C12L14 carbon steel construction for reliable strength in metal parent materials
• Smooth, rolled finish for consistent installation and thread engagement
• Overall length of 21/32 inches (0.656 inches) suits typical fastener depth requirements

Compatibility

Designed as an OEM-style threaded insert for use in metal parent materials tapped to a 5/8-11 thread, accepting 7/16-20 UNF fasteners - suitable for thread repair and reinforcement applications in mechanical and industrial assemblies.

Installation Notes

Installation is typically performed by machinists, maintenance technicians, or mechanical tradespeople. The parent material hole must be tapped to the correct 5/8-11 specification before driving the insert. Power down and de-energize any associated equipment before beginning thread repair work on in-service machinery. Do not exceed the rated thread engagement depth for the parent material, and verify insert seating is flush or below the parent material surface before torquing any mating fastener.