Could a Bolted Assembly Specialist help solve your bolted assembly issues?


We speak with Alexandre Perrier – Bolted Assembly Specialist at Boltistruct – on how mechanical engineers can overcome their bolted assembly issues.

Alexandre runs his own engineering consultancy specializing in bolted assemblies. He previously worked at CETIM – the French Technical Center for Mechanical Industries.

What are the most common customer fastener problems and issues that you see?

The most common issues customers have with their bolted assemblies are bolt failure due to breaking or loosening, incorrect tightening instructions, and unsuitable material and design choices for demanding applications.

What does your company offer in terms of fastener solutions for customers?

I created the company Boltistruct to help customers and their mechanical engineers to make their bolted assemblies more reliable. We first identify the root cause of failure. We often see that failure is caused by multiple issues that can have a culminative negative impact on the bolted assembly.

Once the root causes have been identified, we can perform detailed analyses and calculations to develop solutions to overcome the issues – both in the short and long-term. These may be presented as guidelines or training for engineers involved in the design, installation and maintenance of equipment.

In your opinion, what are the strategic areas for improvement related to bolted assemblies?

Many issues can be avoided during the design phase as well-designed assemblies can avoid issues. Training is also key to raise awareness among even experienced mechanical engineers on how issues can be avoided by using the latest techniques and solutions available.

The bolting industry has developed significantly over the past decade, but knowledge in the mechanical engineering industries has not necessarily kept up to date with these developments or best practice. Significant improvements can be made by improving knowledge of the friction coefficient for tightening instructions – as well as of the interface friction coefficient between parts for non-slip design criteria.

What problems do you see with standard stainless bolts?

The improper use of standard stainless steel bolts is a key issue as their mechanical properties are typically not as good as that of carbon steel. This can also lead to galling issues when not using lubricants for tightening. But there are great solutions already available – such as BUMAX fasteners.

Have you worked with BUMAX fasteners?

I have just completed a project for a customer in France where we used BUMAX® 109 bolts on a bolted assembly for a steam sterilizer. Stainless steel is needed for its corrosion resistance on the application, but standard stainless steel didn’t have the mechanical strength or level of tightening to cope with the vibrating sterilizer. We actually redesigned the machine with BUMAX bolts and the customer has now redesigned their next machine with BUMAX too.

What are the benefits of using BUMAX?

I guess the main customer benefit is reliability. BUMAX fasteners offer excellent mechanical properties for tightening and not loosening unexpectedly. The high-quality material and thread also help avoid galling issues.

Additionally, I think that BUMAX can be really useful for customers that want to downsize their equipment – either by using fewer bolts, or smaller or more lightweight parts.

What will your next BUMAX project be?

I am currently finalizing an order for a customer in the nuclear industry. They have had issues with standard stainless steel bolts galling, so I am creating guidelines for their future material choices. I am confident that BUMAX can offer them a great solution to overcome their galling issues.

About Alexander Perrier

Alexander is a mechanical engineer that has worked as a bolt assembly specialist since 2016. He founded Boltistruct in 2022 and works with various customers in automotive and mechanical industries.

Contact Alexandre directly at



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