E-z Lok TH-420-SV Brass Threaded Insert 1/4-20 Unc

Product Description

The E-Z LOK TH-420-SV is a brass single vane tapered hole threaded insert designed to create durable, load-bearing internal threads in plastic components. Sized at 0.375 inches in diameter with an overall length of 0.3 inches, this insert installs into a tapered pre-drilled hole and relies on a single vane to resist rotation and pullout once seated. The 1/4-20 UNC thread standard makes it compatible with widely available fasteners used across industrial, electronics, and consumer product assembly. Installation is performed by machine shops, assembly technicians, and maintenance professionals working with plastic housings, enclosures, and structural plastic parts.

This insert is intended for use in plastic substrates where a reliable threaded connection is required without molded-in threads. The tapered hole design allows the insert to be pressed or driven into a pre-drilled hole whose diameter tapers from 0.349 inches at the small end to 0.363 inches at the large end. A pilot diameter of 0.354 inches guides alignment during installation. Typical applications include injection-molded plastic enclosures, electronic housings, and plastic structural assemblies where repeated fastener engagement is needed. The brass construction provides corrosion resistance and good thread wear characteristics relative to the surrounding plastic material.

Key Features

• Brass construction for corrosion resistance and long-lasting thread integrity in plastic assemblies
• Single vane design resists rotation and pullout within the tapered hole installation
• 1/4-20 UNC thread size for compatibility with standard inch-series fasteners
• Tapered hole installation with small end hole diameter of 0.349 inches and large end of 0.363 inches
• Compact 0.3 inch overall length suits thin-wall and space-constrained plastic parts
• Minimum wall thickness requirement of 0.194 inches guides proper material selection for host parts

Compatibility

Designed for installation into plastic substrates requiring 1/4-20 UNC threaded inserts with a tapered hole installation method. Host material must provide a minimum wall thickness of 0.194 inches to ensure proper retention.

Installation Notes

Drill or machine the host plastic to the specified tapered hole dimensions before installing this insert. Ensure the workpiece is secured and stationary before pressing or driving the insert into place. Verify minimum wall thickness of the plastic substrate meets the 0.194 inch requirement to prevent cracking or insert pullout. Follow the tooling and installation torque guidance provided by E-Z LOK for this insert series to avoid damaging the plastic host material.