Mechanical Engineer

Safety Bolt; Stockholms kommun; On-site; SEK 700,000 - 950,000; Full time

Job summary

Safety Bolt is a Swedish startup delivering retrofittable sensors that measure clamping force in bolted joints to provide long‑term structural integrity data for critical infrastructure. We seek a senior mechanical engineer with deep bolt mechanics expertise to own the hardware design, test rigs, and cross‑functional work with EE and firmware teams.

In this broad, hands‑on role you will prototype, test, and iterate mechanical components, mentor design decisions, and help scale production for a

Qualifications

• Solid knowledge of preload theory, friction, relaxation, and failure modes.

Responsibilities

• Be the internal expert on bolted joint mechanics.
• Lead concept generation for how the Safety Bolt sensor fastens to bolts.
• Own the mechanical design of in-house test rigs and custom equipment.
• Contribute to material selection, tolerances, and structural decisions.
• Ground system-level discussions with EE and FW using mechanical reality.
• Carry out CAD work in early phase; hand off CAD execution later.

Skills

Bolted joint mechanics

Materials engineering

Cross-disciplinary collaboration

Hands-on hardware

CAD proficiency

Independent ownership

Education

MSc in Mechanical Engineering

BSc with bolted joint experience

Tools

SolidWorks

CATIA

Creo

Job description

Safety Bolt

We're Safety Bolt and given our recent €2.6M fundraise and €13M LOI, we're seeking highly driven, top 1% talent to join our team and scale our monitoring solution to a multi billion euro infrastructure market.

Safety Bolt

We're Safety Bolt and given our recent €2.6M fundraise and €13M LOI, we're seeking highly driven, top 1% talent to join our team and scale our monitoring solution to a multi billion euro infrastructure market.

If you're simply looking for a job, this is not for you. We seek highly motivated people who proactively and obsessively strive to solve novel problems all the way to product launch and beyond, fundamentally changing the way we build, maintain and monitor physical structures.

What We Do

We build retrofittable sensors that measure the clamping force inside a bolted joint. Using magnetostrictive sensing, each sensor reads the stress in a standard steel bolt without touching it and without modifying the joint, then reports over LoRaWAN to a cloud platform where trend analysis reveals developing risk long before an inspection would. It clips on in under a minute and delivers structural integrity data for up to twenty years.

Bolted joints hold up critical infrastructure everywhere: wind energy, bridges and civil infrastructure, rail, tunnels and mining, and heavy process industry. A single wind turbine alone holds over a thousand bolts whose tension is checked by hand, if at all, and loss of preload is one of the main drivers of structural failure. The same sensor addresses all of them.

Why now

With ex-McKinsey leadership, we have developed and patented industry-leading technology over the last 7 years and recently reached a technical breakthrough, enabling an oversubscribed seed round with top-tier investors (to be announced), selection as one of Sweden's top 33 startups, a place in NATO's DIANA program chosen out of 3400 startups, and a Letter of Intent to purchase 47 000 sensors.

Vision:

Become the leading structural integrity data provider globally

Target:

Volume production and distribution of retrofitted sensors, providing 20 years of structural integrity data

Culture:

Truth seeking, high agency, pragmatic, entrepreneurial and hypothesis driven

Seeking:

Exceptional drive, intelligence and integrity. Lead rather than follow.

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The Role

You will be Safety Bolt's internal expert on bolted joint mechanics, material behavior, and structural integrity, and much more besides. In a company of this size, your role will be broad by design: you will contribute to sensor fastening concept development, own the mechanical design of test equipment, and act as a technical sounding board across the team. The foundation of the role is deep knowledge of how bolted connections work, how they fail, and what governs their behavior over time. On top of that, you will need to be comfortable rolling up your sleeves and doing hands‑on mechanical work, CAD, and creative problem‑solving, often in areas that cross into electronics and measurement.

What you will do

• Be the internal expert on bolted joint mechanics: preload, friction, relaxation, and failure modes
• Lead or contribute to concept generation and evaluation for how the Safety Bolt sensor fastens to bolts, assessing concepts for installation simplicity, manufacturability, and long‑term retention security
• Own the mechanical design of in‑house test rigs and custom test equipment built with or for external partners
• Contribute to material selection, tolerance analysis, and structural decisions in the product design
• Act as a cross‑disciplinary partner to EE and FW: the person who grounds system‑level discussions in mechanical and materials reality
• Carry out CAD work in the early phase; over time, hand off CAD execution while maintaining design ownership

Must have

• Solid knowledge of bolted joint mechanics: preload theory, friction coefficients, relaxation, and failure modes
• Materials engineering foundation: understanding of steel alloys under stress, fatigue loading, surface treatment, and corrosion
• Comfortable working across a broad and shifting scope, from detailed design work to technical discussions with external test institutes and partners
• Hands‑on and experimental mindset: willing to build, test, adjust, and iterate on physical hardware
• CAD proficiency for design of mechanical components and fixtures (SolidWorks, CATIA, Creo, or equivalent)
• High ownership and independent drive: you define your own work agenda and take problems to conclusion

Nice to have

• Experience designing mechanical test fixtures or custom structural test setups
• Background in industries where bolted joint integrity is safety‑critical: wind energy, heavy infrastructure, mining, marine, or process industry
• Experience working with external test institutes or structural certification bodies
• Familiarity with fatigue analysis or FEM for structural components
• Interest in or exposure to sensor technology and measurement systems
• Experience in a startup or small‑company environment with a broad and evolving scope

Education

MSc in Mechanical Engineering, Materials Engineering, Structural Engineering, or equivalent. A BSc with substantial, documented experience in bolted joint mechanics or structural integrity is considered.

Experience level

5+ years in mechanical engineering with clear, documented exposure to bolted joint systems, fastening technology, or structural integrity in a load‑bearing context. We are not looking for a generalist who has encountered bolts; we are looking for someone for whom this is a professional specialty.