Screw Thread Inserts
It’s important to create threads that last and can be reused in many fastening situations — whether in metal, wood, or plastic. That’s where screw thread inserts come in. They create durable threaded holes that extend the life of your assembly and make repairs easier.
At E-Z LOK™, our threaded inserts are designed to quickly and reliably solve common problems caused by thread wear.
What Are Screw Thread Inserts?
A screw thread insert — also known as a threaded insert, insert nut, or threaded bushing — is a small, cylindrical component with internal threads. It is installed into a pre-drilled hole, with installation methods varying depending on the insert type and application.
Once in place, it adds a new threaded surface that can accept screws or bolts repeatedly without damaging the surrounding material.
Threaded inserts are especially useful when:
- The base material is soft (such as aluminum, magnesium, wood, or plastic)
- Threads must be assembled and disassembled frequently
Without an insert, repeated use can wear down or strip the original tapped hole.
Why Use Threaded Inserts?
Durability
Inserts create wear-resistant threads that extend the life of your bolted joint.
Repair and Reinforcement
They are often used to repair stripped or damaged threads.
Material Protection
In softer materials, inserts distribute the load and help prevent thread failure.
Reusable Threads
Once installed, inserts allow screws and bolts to be removed and reinstalled many times without damage.
At E-Z LOK, our inserts are designed for straightforward installation using commonly available tools, though some types may require specific drills or taps depending on the application. Solid wall inserts also feature a dry, self-locking adhesive that engages quickly to provide strong holding power.
Understanding the Difference Between Screws and Bolts
To fully understand how threaded inserts work, it helps to know basic fastener terminology.
Screws
Screws are externally threaded fasteners that engage with a preformed internal thread, such as a tapped hole or insert. When installed, they may cut or form threads and are typically tightened by turning the head.
Bolts
Bolts are also externally threaded, but they are generally used with a nut on the opposite side of the assembly. Bolts pass through aligned holes in the materials being joined and are secured by tightening the nut.
In both cases, the internal threads that screws or bolts engage with are critical. If those threads wear out, the joint becomes unreliable.
That’s where screw thread inserts shine — they provide new, strong internal threads for both screws and bolts to engage with.
How Threaded Inserts Work
Most threaded inserts feature two sets of threads:
- External threads – These grip and anchor into the base material.
- Internal threads – These accept the screw or bolt.
For example, E-Z LOK’s solid wall and helical coil inserts are engineered for maximum pull-out strength with minimal outside diameter. Solid wall inserts use external threads to anchor securely in the base material, while helical coil inserts expand into a hole tapped with a special STI tap to create durable internal threads.Once installed, the internal thread becomes the new mating surface for your fastener — even in materials that previously could not hold threads well.
Inserts make it possible to use standard fasteners in applications where threads might otherwise strip or fail.
Common Applications
Screw thread inserts are used across many industries and assemblies, including:
- Automotive and aerospace components that require frequent reassembly
- Machinery and equipment exposed to heavy loads or vibration
- Woodworking projects that require strong threads in soft wood
- Plastic housings where molded-in threads are weak or unavailable
They offer a simple way to create long-lasting, reliable threads in almost any material.
Choosing the Right Insert
When selecting a threaded insert, consider:
- Material compatibility (aluminum, wood, plastic, etc.)
- Thread size and pitch (metric or imperial)
- Installation method (screw-in, press-fit, heat staking or self-tapping)
E-Z LOK offers a wide range of inserts engineered for specific materials and applications — all designed to make strong threads easy to achieve without specialized tools.
Summary
Screw thread inserts are a durable and versatile solution for repairing or reinforcing threaded holes in a variety of materials.
With E-Z LOK products, installing threaded inserts is simple, reliable, and built for long-term performance.