Screw locking

Chemical thread retention methods

Securing and sealing joints with precoated threads.

Adhesive, locking, sealing

Chemical thread retention methods – The advanced solution for a high degree of security, ease of processing and efficient series production

Unsecured threaded connections can lose their preload force if subjected to vibrations or dynamic loads. This means that components are no longer held together securely. In the worst-case scenario, the threaded connection may fail completely. To avoid such failure Böllhoff offers a wide range of chemical thread retention solutions, which are designed to cover different requirements and applications.


Method / principle

The threads are precoated with an appropriate chemical thread retention product, depending on the required function. There are two main product types: micro-encapsulated precoatings, which cure when the screw is fastened, and polyamide spot precoatings, which bring about a locking retention effect in the thread.

Applications

Any thread can be precoated with a chemical thread retention product, regardless of shape and size and of whether it is a standard or a custom-made part. These products are suitable for a wide variety of applications, thanks to a broad temperature range and their resistance to most oils and greases.

Product benefits
  • Good, reliable retention and locking effect
  • Simple, safe assembly
  • Effective seal
  • No change in component geometry
  • Removable

Product benefits

There are many good reasons for using our products.

Strength and options.
Point by point.

Reliable and dependable

Very safe, no risk of forgetting the lock washer or the anaerobic adhesive.

Reduced assembly times

No additional fitting of a sealing and retention element required.

Ideal for series production

Reproducible, defined assembly values and easy, problem-free storage.

Easily integrated

No geometric changes necessary; can be integrated into existing applications.

Can be tailored to customer applications

Individual coatings possible, depending on requirements and customer specification.

Detailed description

 

Thread precoating

Böllhoff provides an alternative to anaerobic adhesives in the form of precoated chemical thread retention solutions, which may be adhesive, locking or sealing. Precoating has the advantage that the coating no longer has to be applied manually during assembly. Instead, the process takes place before the fastener is supplied. There are two types of chemical thread retention methods: adhesive micro-encapsulated and locking polyamide coatings.

Position of the chemical thread lock with detailed view of micro-capsules

Position of the chemical thread lock with detailed view of micro-capsules

 

Micro-encapsulated precoating

The pressure and/or shear forces produced as the fastener is tightened cause the micro-capsules to rupture. The adhesive contained in the capsules then combines with a hardener. This results in a chemical reaction (polymerisation) and hardening of the adhesive (adhesive bonding), thereby producing the desired locking effect. Bonding the internally and externally threaded components in this manner is a reliable way of preventing loosening of the threaded connection.

 

Locking thread precoating

The locking precoating method involves applying a polyamide spot to a section of the thread. The axial clearance between the external and internal threads is filled by the coating, which results in high surface pressure between the coated thread and the flanks of the uncoated mating thread. The screw is securely locked in position to prevent loss.

Product variants

Every project deserves a tailor-made solution.

Learn more about the product types and find the right variant for your particular application.

(see DIN 267 Part 27)

Micro-encapsulated precoating

The pressure and/or shear forces produced as the fastener is tightened cause the pre-applied micro-capsules to rupture. Bonding the internally and externally threaded components in this manner is a reliable way of preventing loosening of the threaded connection.

More
(see DIN 267 Part 28)

Locking thread precoating

The locking precoating method involves applying a polyamide spot to a section of the thread. The axial clearance between the external and internal threads is filled by the coating, which results in high surface pressure between the coated thread and the flanks of the uncoated mating thread.

More

Downloads

Find out more: related downloads.

If you would like to know more, simply download the relevant brochures.

Title Language Version File Download
Chemical thread retention methods
Adhesive, locking, sealing
English 8225/15.01 409 kB / PDF
English 8225/15.01 409 kb / PDF

To view PDF documents, you will need the free Adobe Acrobat Reader.

More information

Would you like to discover more of the World of Joining?

Here you will find information about successful applications and related topics.