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All about Intervis® slotted threaded inserts

Paul Gardette
,
18/6/2024
Contents

What are the characteristics of Intervis®? 

In soft and medium-hard materials (light alloys, plastics, compressed wood), threaded fasteners have little resistance to repeated stress. If the screw is tightened too vigorously or too frequently, the threads pull off and the part is out of order.

Stronger fasteners can be used, such as overmolded threaded bushes or thread inserts, but these solutions can be restrictive in use, as they are more difficult and time-consuming to install, and sometimes more costly.  

At LGC Industries, we have registered the trademark Intervis® trademark, which is a threaded insert with a slot, also known as a self-tapping socket

Intervis® are used in the same way as a tap, enabling them to be screwed directly into a smooth hole. A hole simply has to be drilled beforehand. The insert itself cuts the thread into the material for extra security and strength. 

We recommend using Intervis® inserts in aluminum assemblies, as their surface treatment eliminates the electrolytic torque between the two materials. Drilling groups are an average indication. During installation, it is advisable to carry out a trial run by drilling 1/10th above or below the indicated diameter, to take account of the particular characteristics of certain materials.

Intervis® offer several advantages:

  • No pre-tapping, the insert is perfectly anchored in the material
  • No play between spacer and part 
  • Extremely high tensile strength
  • With 30% to 40% overlap, Intervis® achieves maximum pull-out resistance
  • Eliminates thread wear 
  • Increased safety in use

LGC Industries offers several ranges ofIntervis®. First of all, they can be produced in a variety of materials, such as Crude Steel (SCTA), Chromium 6-free Zinc-plated Case-hardened Steel (SCT), Brass or Stainless Steel. 

Don't hesitate to consult us if you're not sure which Intervis to choose, or which material to use, our technical experts will help you make the right choice.

How are Intervis® made? 

To begin with, a threaded insert is a metal fastener with a thread inside the hole, as well as an external thread. Its main feature, in addition to the threads, is its slot. 

The start of the Intervis® manufacturing process is similar to that for conventional sockets. 

The first stage is the external threading of the coil of raw material. This stage is called rolling, as the Intervis® passes between 3 rollers, and the rolling system cold-forms the part by compressing it to create the thread. The advantage of cold forming is that it reinforces the material's elastic resistance. Thus, a threaded insert in rolled material will have better pull-out resistance than a rolled material. 

The second step is to cut the raw material tube on a suitable machine. The tube is cut to the desired length. Chamfers or finishing touches can be added to the material. 

Next, the self-tapping socket is milled. A milling cutter cuts the part, creating the characteristic Intervis® slot. 

The final stage is tapping, i.e. the internal threading of the Intervis®. To do this, a rotating tap passes inside the part to give it a thread. 

Intervis® 3 holes

What are the Intervis® applications? 

In the automotive industry, self-tapping threaded inserts are found in car headlamps and in aluminum or plastic housings. 

Car headlights

In non-automotive applications, Intervis® are used in overmolded assemblies, where the mold is housed in the part's threads, while the part's tap acts as a thread for the fastener to be screwed in. 

In the automotive sector, Intervis® 3-hole fasteners can be used in door fasteners. The 3-hole design ensures better load distribution and more robust fastening.

Car door

For non-automotive applications, Intervis® 3-hole brackets can be used to secure electronic equipment housings.

Conclusion 

It's important to choose the right fasteners for your application. Intervis® self-tapping sockets, for example, must be chosen with care to ensure that parts are held securely in place. 

At LGC Industries, we've been experts in cylindrical fasteners for 85 years. Our aim is to help our customers co-design the right product for their needs. That's why you can easily contact us on our website so that we can support you in your project and meet your specifications. 

Thanks for reading and see you soon at LGC Industries! 

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