Your result
Locking ability |
3 out of 5 |
Reusability |
1 out of 5 |
Worker safety |
4 out of 5 |
Initial cost |
Medium |
Lifetime cost |
Medium |
Locking ability |
3 out of 5 |
Reusability |
1 out of 5 |
Worker safety |
4 out of 5 |
Initial cost |
Medium |
Lifetime cost |
Medium |
Serrated lock washers increase the friction between the bolt head/nut and the mating surface. They do this by gripping into the mating surfaces. Serrated lock washers are installed between the bolt head/nut and the mating surface. The bolted joint is then tightened in the same way as an unsecured bolt. If the bolted joint experiences a loss of tension, the washer is no longer effective and must be replaced.
Single part serrated washers can damage painted/coated surfaces because they have a tendency to rotate with the fastener. This risks damaging the surface, cracking the paint/coating and causing corrosion.
Read the full version in the eBook "Why do bolts loosen?"
(A comparison between common bolt securing options)
Scroll down to access the ebook.
The biggest challenge for a bolted joint, causing it to lose preload and fail, is spontaneous loosening often caused by vibrations. This Junker test shows all 5 nuts rotated loose! A steep decline in the graph indicates a failure. Read more about the Junker Test.