E-z Lok 303-720 Thread Locking Insert 7/16-20 Unf Stainless

Product Description

The E-Z LOK 303-720 is a self-locking threaded insert machined from 303-grade stainless steel, designed to provide a secure, vibration-resistant internal thread in materials where thread integrity is critical. The insert 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). It is installed into a pre-tapped or drilled host material using a standard tap, making it a practical choice for maintenance technicians, machinists, and field service professionals who need to repair or upgrade threaded connections in metal assemblies.

This insert is suited for applications where a stronger or locking thread is required in aluminum, soft steel, plastics, or other base materials. The self-lock wall design applies radial pressure against the mating fastener to resist loosening under vibration or cyclic loading. Typical use cases include equipment repair, custom fabrication, and thread-size conversion in industrial and mechanical assemblies. It is appropriate for both shop and field installation scenarios.

Key Features

• Self-lock wall design resists loosening under vibration and dynamic loads
• 303 stainless steel construction provides corrosion resistance and durability
• 7/16-20 UNF internal thread with a 2B class of fit for standard fastener compatibility
• 5/8-11 external thread with a 2A class of fit for installation into standard tapped holes
• 21/32-inch overall length (0.656 inches) suits shallow to moderate-depth host materials
• Bright finish with no coating that could affect thread tolerances
• Compatible with standard tap types - no specialty tooling required for installation

Compatibility

Designed as an OEM-style threaded repair and conversion insert for host materials tapped to accept a 5/8-11 external thread, delivering a 7/16-20 UNF internal thread in the installed position.

Installation Notes

Installation is performed by machinists or maintenance technicians using standard hand or machine tapping equipment. The host material must be tapped to 5/8-11 prior to driving the insert. De-energize or lock out any equipment before servicing threaded connection points. Avoid over-driving the insert beyond the specified overall length to prevent damage to the host material threads.