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FAQ - Frequently Asked Questions


Can the thread inserts be used to repair a damaged thread?

Yes, absolutely, using thread inserts you can restore a thread to its original size and technical characteristics. Moreover you get a thread that is even more stable than it was before the repair. In general, helicoil thread inserts are used in space, naval, aeronautical, military, railway industries to strengthen the threads and make them more robust

What is the difference between a Spiralock thread insert and a Helicoil thread insert?

This is the same product, known as helicoidal inserts, produced by different companies

What is the difference between a Helicoil thread insert and a Tangless thread insert?

The tangless thread insert has no drive tang. So you save in the tang breaking time. But it costs a little bit more, plus you should add additional cost of installation tool. Usage of Tangless thread inserts is economically justified when they are installed in large volumes

What is the difference between a Helicoil thread insert and an Ensat self-tapping insert?

Both products strengthen a thread or repair a damaged thread in low shear strength materials. The most significant difference is the size. Self-tapping bushes are larger. On the other hand, the thread insert is an elastic component which better follows the thermal movements of the carrier material

Is it possible to buy thread inserts in stainless steel?

The thread inserts are always in AISI 304 stainless steel. On request they can be supplied in marine stainless steel, AISI 316

How do I check if the thread insert has the correct length?

The length of the thread insert in a free state is measured in number of coils, comparing with the Helicoil pdf table in our catalogue. In a free state the thread insert can be more extended or compressed; therefore, no measurement with the caliper is valid

Do left thread inserts exist?

Certainly, on request we can deliver thread inserts for left-hand pitch screws and also left-handed taps and installation tools

Do inch thread inserts exist?

Of course, both UNC and UNF versions present in the shop and also GAS, BSW, NPT versions available on request

What are self-locking thread inserts used for?

This type of thread insert has a polygonal coil which exerts pressure on the screw, preventing it from being easily unscrewed in the presence of vibrations. Self-locking threads are available upon request

What is the difference between a finishing tap and a tap for blind holes?

The tap for blind holes is also suitable for machine use, it has spiral flutes to remove chips . Also, it tap deeper as it has a flat point. See our thread insert STI taps in the catalogue

What is included in the Helicoil Kit?

Our one-size thread repair kit contains the installation tool with pre-winder, the finishing tap and some 1.5D long thread inserts. Multidimensional kit contains the most popular sizes in the various pitches available, see thread kit table for details


What is the difference between an Ensat self-tapping bush and a Helicoil thread insert?

Both products reinforce a thread in brittle materials or are used to repair a damaged thread. The most significant difference is the footprint, which is larger in case of the self-tapping bush. In addition, the thread insert is an elastic component, which better follows the thermal movements of the material

What is the difference between the Ensat 302 , Ensat 307 and Ensat 308 bushes?

The Ensat 302 bush, with two cutting slots, is the most popular and recommended for most common applications. It has a slight self-locking effect on the screw when installed in particularly hard materials.

Ensat 307 and Ensat 308 bushes have three cutting holes and, for the same insertion torque, exert a higher and better distributed cutting force than bushes with cutting slots, having three cutting points instead of two. For this reason they are particularly recomended for use in very hard materials. In addition, there is no braking effect on the screw.
The 307 series is also shorter and therefore ideal on thinner materials

Are the threaded bushes produced in standard sizes?

That's right, our self-tapping bushes have the standard Ensat 302, 307 and 308 sizes

Should I cut a thread in the hole before installing the self-tapping insert?

No, the bush is self-tapping. It creates the tapping in the appropriately sized hole by itself when screwed in

What is the correct hole size for the self-tapping bush?

The size is indicated in the technical datasheet and depends on the type/hardness of material used

Can I use the self-tapping bush as a thread reducer

Yes, in this case it might be advisable to use a drop of glue to fix the bush to the piece and avoid unscrewing

Is there a special tool to insert the self-tapping bush?

Yes, we have manual and machine installation tools for self-tapping bushes. If you have to install just a few bushes it is possible to use a screw equipped with a nut and locknut


Why are there so many types of threaded inserts for plastic?

There are inserts to be cold-inserted (expansion, self tapping, and press-in); to be heat/ultrasonic-inserted; or to be embedded during molding (co-molding). Each insert is designed for the specific application and to offer a wide range of solutions. For example, there are short version inserts for lower studs or flanged inserts for greater contact

Does the choice of insert depend on the hole available?

Absolutely, if you have already prepared holes, it is important to choose inserts compatible with that hole size. You can consult the technical table to check insert sizes and hole sizing

Why should I use a brass threaded insert and not a self-tapping screw?

The insert creates a durable and robust thread for metric or inch (UNC and UNF) screw. You can then screw and unscrew as many times as you wish without the risk of wearing out the plastic. In addition, brass inserts are specifically designed for plastics and offer a greater seal than the screw


What is the difference between the Plas-Fix screw and the Plas-Tech screw?

Both are self-tapping screws designed for use in plastic materials. The Plas-Fix, with its three-lobed profile, induces less tension in the material

What materials are screws for plastic designed for?

In general they can be used in all thermoplastics (such as ABS, polyamide e.g. Nylon 6-6, PVC and polycarbonate), thermosets, and also epoxy, polyester resins or Bakelite

What hole should I prepare to insert a screw for plastic materials?

The holes are indicated in the technical table for the type of screw chosen. Correct hole sizing is important to get the best performance from the screw

Is the Plas-Fix 45° screw trilobed?

Yes, this screw has a shank of triangular cross-section.

Is the Plas-Tech 30° screw trilobed?

No, this screw has a cylindrical profile shank while having a specific pitch and configuration for plastic. It is the equivalent of the PT screws


How to extract a broken tap?

Remove all chips of the broken tap. Insert the fingers of the tap extractor into the flutes of the broken tap. Push the holder down until it touches the broken tap. Slide the sleeve down until it touches the work. Apply a tap wrench to the square end of the holder. Twist forward and backward a few times to loosen, then back out the broken tap

Is it possible to extract a helicoil STI tap with tap extractors?

No, only taps with straight flutes can be extracted, both hand or machine, regardless of the pitch and whether they are metric or not

Can the fingers of the tap extractor be broken?

The fingerss are very strong, and if you lower and fix the protective sleeve well, they should not bend or break. In case they do, we have replacement finger kits in our catalogue

Filetti riportati Domande e risposte
Inserti filettati per plastica Domande e risposte
Viti autofilettanti per plastica Domande e risposte
Estrattori di maschi rotti Domande e risposte
Bussole autofilettanti Domande e risposte
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