‍What is a self-threading insert?

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Self-threading inserts are indispensable should you wish to make repairs or threads in materials that cannot be tapped.

Oftentimes in soft and medium-hard materials such as light alloys, plastics or even compressed wood, taps do not withstand repeated stresses. If a screw is tightened too forcefully or too frequently, the threads may break off, making the part unusable.

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This is where the self-threading insert (aka "threaded insert" or "threaded dowel pin") comes in!

Self-threading inserts can be solidly anchored in the material in which they are installed, because the threaded dowel itself creates its own thread during assembly. With this type of self-threading dowel, there is no need to drill a hole in advance, unlike conventional threaded inserts; nor to drill a hole and then tap like when installing a helicoil. This means that self-threading inserts offer increased pull-out resistance when trying to loosen.

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Intervis self-threading inserts have a standard (interior) thread as well as an external thread.

• An external thread truncation.
• Two sharp-edged slots.

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You can screw the insert straight into a smooth hole drilled beforehand, just like you would with a tap.

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Threaded insert, self-tapping threaded insert: advantages of Intervis®

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At LGC Industries, we developed the Intervis brand - an innovative threaded insert, also known as a self-threading bush / bushing.

The Intervis threaded insert is a practical tapping and screwing solution, allowing you to insert it directly into a pre-drilled hole. Thanks to its ability to carve its own thread into the material, self-threading inserts guarantee additional safety and solidity.

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We recommend using Intervis self-threading inserts in your aluminium assemblies as its surface treatment eliminates the electrolytic couple between the two materials. Gang drilling machines provide an average indicator. When installing the insert, it is advisable to do a test by drilling 1/10th above or below the indicated diameter due to the particular characteristics of certain materials.

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Intervis® self-threading inserts offer several advantages, e.g.:

• They can be inserted into the material without any need for pre-tapping
• No clearance between the spacer and the part
• Excellent pull-out resistance: Intervis® inserts reach their maximum pull-out resistance at 30% to 40% overlap
• No wear from tapping
• Absolute safety during use

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At LGC Industries, we offer several ranges of Intervis® self-threading sockets available in various materials such as crude steel, chromium(VI)-free case-hardened and zinc-plated steel, brass or stainless steel.

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The different types of Intervis® self-threading inserts

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Intervis standard slotted self-threading insert

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The standard Intervis® slotted threaded insert can be inserted straight into a hole drilled beforehand. It functions as a tap, creating a thread in the hole by itself. This type of fastening is ideal for medium-hard materials such as light alloys, compressed woods or plastics. The installation of this self-threading bush is simple and effective.

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Intervis self-threading insert with 3 holes

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With our low-height Intervis® self-threading inserts, we have added three holes onto the self-threading insert in order to facilitate evacuation of material chips / swarf when tapping the assembly material.

In short, the Intervis® 3-hole threaded insert is a practical alternative to the standard Intervis® 1-slot threaded inserts in applications involving smaller heights and thicknesses.

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Want to find out more about our Intervis® self-threading sockets?

Go to our dedicated article: Everything you need to know about Intervis® threaded inserts

All of our Intervis® self-threading inserts are available in:

• Stainless steel
• Steel
• Brass