What are the main characteristics of Intervis® inserts?

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In soft and medium-hard materials (light alloys, plastics, compressed wood), taps (internal threads) are not very resistant to repeated stress. If you tighten the screw too vigorously or too often, the threads can be ripped off, making the part unusable.

Fortunately, other more resistant fasteners can be used instead, such as over-moulded threaded dowel pins or threaded inserts, but these solutions can be somewhat limited as they take longer and are more complicated to install, as well as being more expensive.

At LGC Industries, we have registered Intervis®, our threaded slotted insert, as a trademark. This type of insert can also be called a self-tapping dowel pin.

Intervis® inserts work like a tap, allowing you to screw directly into a smooth hole. All you need to do is make sure this hole is drilled in advance. The insert itself carves the thread into the material to ensure additional security and strength.

We recommend using Intervis® inserts in aluminium assemblies as their surface treatment eliminates the electrolytic couple between the two materials. Drilling groups are an average indicator. When installing the piece, it is advisable to carry out a test by drilling 1/10th above or below the indicated diameter to account for each material's particular characteristics.

Intervis® inserts offer several advantages:

• Without any need for pre-tapping, the insert carves itself perfectly into the material
• No clearance between the spacer and the part
• Very high pull-out resistance
• Intervis® inserts reach their maximum pull-out resistance at 30% to 40% overlap
• Prevents internal thread from getting worn out
• Increased safety during use

At LGC Industries, we produce several ranges of Intervis® inserts. They come in various materials such as crude steel, zinc-plated steel (chromium 6-free), brass or stainless steel.

• The 3-hole intervis® has 3 equidistant cylindrical holes on its outer surface
• The Intervis® threaded slotted insert has two lengthways slots on its sides

Please don't hesitate to contact us should you have any queries when choosing your Intervis or material. Our team of technical experts will be happy to advise you.

How are Intervis® inserts made?

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A threaded insert is a metal fastener comprising a tap (i.e. an interior thread) and an external thread. Its defining feature, in addition to these threads, is its slot.

With Intervis® inserts, the beginning of the manufacturing process is similar to that of conventional dowel pins.

The first step is the external threading of the raw material coil. This stage is called roll bending because the Intervis® goes between three dies as the rolling system cold deforms the part by compressing it to create the thread. The advantage of cold forming is that it strengthens the elasticity of the material. In this way, an internally threaded insert inside roll-bent material will have better pull-out resistance than that of a laminated material.

Then the second step is parting the raw material tube in a suitable machine. The tube is now cut to the desired length. Chamfers or finishes can also be added to the material at this time.

The third step is countersinking the self-tapping dowel pin. A milling tool cuts the part, giving our Intervis® insert its distinctive slot.

The final step is tapping, i.e. making the Intervis® insert's internal thread. To do this, a rotating tap will make its way around the inside of the part to give it a thread.

What are some example applications for Intervis® inserts?

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In the automotive sector, slotted self-tapping threaded inserts can be found in car headlights as well as in crankcases made out of aluminium or plastic.

Outside the automotive sector, Intervis® inserts are used in overmoulded assemblies - the material "flows" into the threads of the part while the part's tap acts as a thread for the fastener that is being screwed inside.

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The 3-hole Intervis® insert may also be found in car door fasteners, the 3 holes allowing for better load distribution and more robust fastening.

Outside the automotive sector, the 3-hole Intervis® insert can be used in fastening cases for electronic devices.

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In short

It is important to choose fasteners suited to your applications. Intervis® self-tapping dowel pins must be chosen carefully in order to ensure the correct maintenance of the parts.

At LGC Industries, we have over 85 years' experience and expertise in cylindrical fasteners. That's why you can easily contact us on our website: write us a message and we will be able to support and accompany you with your project, including any specifications you may have.

Thank you for reading - hope to see you soon at LGC Industries!