Get in contact with us



+43 (0)732 257700

Contact form

We are happy to answer your questions.

> Contact

Junker vibration test: when does a fastener come loose?

The issue of screw joint vibration safety is of ongoing interest to product developers, production experts, industrial engineers, maintenance and safety officers. The reason for this is obvious: safety takes top priority. So don’t leave things to chance – put your products through an independent Junker vibration test in our laboratory.

What is a Junker vibration test?

The Junker vibration test described in DIN 65151 allows us to compare different fasteners and their ability to maintain clamp load under extreme conditions in just 30 seconds. The test is carried out using a transverse dynamic load. The results provide the design engineer with information about joints design safety and how effective their selected fasteners really are. One exciting element of this type of test is finding out how long the preload force is maintained for, which elements the preload force drops for and how much by exactly. Sometimes, the preload force is lost completely, which can cause major problems.

When should a Junker vibration test be carried out?

Anywhere that joints are exposed to vibrations will put high demands on the fasteners. Typical examples include applications in railway and aviation technology, where joints are exposed to particularly high dynamic loads. In-component vibrations lead to micro-movements and cause screws to come loose by themselves if the fasteners are not secured correctly. This situation must be avoided at all costs. A Junker test will show you whether your screw fastener will really hold.

How the test process works

The DIN 65151 Junker test shows the loss of preload force relative to the duration of a dynamic load. For the test, the screw in question is mounted on a test rig and the clamped parts are subjected to a transverse dynamic load. A load cell is used to measure and record the preload force throughout the test while it is put under a constant transverse load. This not only enables testing of the particular fasteners, but also allows direct comparison with possible alternatives. Our short video shows how the test works in practice.

What are the benefits for customers?

The Junker test is used to determine which fasteners maintain clamp load when under the influence of vibration and which don’t. Having this information helps engineers to design safe joints with a long service life.

Bossard – your expert in Junker vibration tests

Bossard – your expert in Junker vibration tests

Contact our experts and learn more about our Expert Test Services. We are happy to hear from you!


Contact us


Related topics

Discover in our white papers what our experts write on topics such as:

  • Corrosion
  • Friction
  • Hardness measurement
  • Hydrogen embrittlement
  • Material fatigue

Download white papers


Discover other modules that contribute to improving your productivity step by step

Expert Walk
Study your fasteners and tools in use, we determine how to proceed leaner and smarter

Expert Education
Learn about the essentials and secrets of fastenings in our seminars and e-learning courses

Expert Teardown
Identify the best fastening solution and cost saving potential for you

Expert Design
Design your best product with a wide range of technical information and tools

Expert Assortment Analysis
Reduce TCO by identifying opportunities for fastener rationalization