Security screws in mechanical engineering: why a standard Torx screw isn’t enough
In short: A security screw, also known as a security fastener or tamper-resistant screw, is a fastener that can only be removed using special tools. In mechanical engineering, they secure protective covers, control cabinets, and service hatches against unauthorized access. Cinstar® is a security fastener with a specific drive geometry that is available exclusively in the Benelux through SecuFast (Archey).

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In many machines, the biggest safety flaw isn’t found in the software, control system, or sensors, but in something much simpler: the screw on a guard. A standard Torx T20 or Allen screw may seem practical—until anyone can access it.
In practice, protective panels, service hatches, and safety covers are often opened in a matter of seconds using standard tools found in any toolbox. This poses risks to both machine safety and liability. For applications where unauthorized access must be prevented, an increasing number of machine builders are therefore opting for security fasteners such as Cinstar®.
Why standard screws pose a safety hazard
When it comes to machine safety, the focus is often on emergency stops, light curtains, safety relays, guards, and CE compliance with standards such as ISO 14120 (fixed and movable guards). However, the mounting of those guards receives surprisingly little attention. Yet that is precisely where the weak link lies.
A standard Torx, Phillips, or Allen screw can be easily loosened using commonly available tools. This allows operators, third parties, or unauthorized persons to gain access to moving parts, electrical components, or sensitive settings.
This can lead to:
- unsafe situations for staff
- unplanned downtime
- tampering with or sabotage of machinery
- higher maintenance risks
- issues during audits, inspections, or CE inspections
As a result, demand for tamper-resistant fasteners is growing, particularly in the fields of mechanical engineering, food processing, OEM manufacturing, and industrial automation.
What is Cinstar®?
Cinstar® is a security fastener with a unique drive profile: a specific 5-lobe shape with a pin in the center. The profile differs geometrically from standard Torx Pin (6-lobe) or Allen wrenches with a pin, meaning standard bits do not fit. Installation and removal are only possible with the corresponding SecuFast Cinstar® bit, which is available in the Benelux exclusively through SecuFast (Archey). This makes Cinstar® ideally suited for applications where controlled access is essential.
Specifications at a glance
| Drive | Unique 5-lobe geometry with center pin |
| Material | A2 stainless steel |
| Dimensions | M3 through M8 |
| Head shapes | Countersunk head and flat-head |
| Tools | Only compatible with the SecuFast Cinstar® bit |
| Availability | Available directly from stock; exclusively through SecuFast (Archey) in the Benelux |
When should you choose Cinstar®?
The choice of a security fastener depends on the desired level of security. While a standard Torx may be sufficient for general assembly, Cinstar® is the right choice in situations where controlled access is essential. Typical applications:
Control cabinets and switch panels
Electrical components and PLC controls must remain protected against unauthorized access and tampering with parameters.
Protective covers around moving parts
Prevent safety guards from being easily removed during production. This is also a requirement specified in ISO 14120 for fixed guards.
Sensor and encoder housings
Protect sensitive measuring components from being moved out of position or damaged.
Service doors for maintenance personnel
Only authorized technicians with the correct bit are granted access to critical machine components.
Cinstar® compared to other security fasteners
Engineers frequently compare Cinstar® with other secure fasteners. The main difference lies not only in the screw head itself, but primarily in the availability of the corresponding tools.
| Type | Drive | Availability bit | Security level |
| Standard Torx / Allen | Open system | Available everywhere | Low |
| 6-Lobe Pin (Security Torx) | Torx with center pin | Available online and in sets | On average |
| Hex Pin | Allen wrench with center pin | Quite common | On average |
| One-Way Screws | One-way lane | N/A (not disassemblable) | Expensive, poor customer service |
| Cinstar® | Unique 5-lobe geometry with center pin | In the Benelux region, exclusively through SecuFast (Archey) | Tall, with service option |
For many 6-lobe and hex pin systems, bits are readily available online or in standard tool sets. This effectively lowers the level of security in practice. With Cinstar®, the bit is available in the Benelux region exclusively through SecuFast (Archey). This demonstrably raises the level of security in this region and provides control over who has access.
Machine safety starts with the details
In modern mechanical engineering, safety isn’t just about large systems—it’s about the details that are used every day. A guard is only truly safe if it cannot be opened easily. That’s why more and more OEMs, engineers, and machine builders are choosing specialized safety screws as part of their overall safety design.
Frequently Asked Questions About Safety Screws in Mechanical Engineering
What is the difference between a security fastener and a tamper-resistant screw?
In practice, the terms are often used interchangeably. Both refer to fasteners that cannot be opened with standard tools. “Tamper-resistant” emphasizes resistance to tampering, while “security fastener” is a broader umbrella term for all secure screw connections.
Is a Torx screw with a pin (Security Torx) secure enough?
This may be sufficient for light-duty applications. However, the level of security is limited because bits for 6-Lobe Pin and Hex Pin are available for purchase online and in standard tool sets. For critical protective covers or control cabinets, a less common system such as Cinstar® is generally the better choice, precisely because the bit is not readily available.
In what sizes and materials is Cinstar® available?
Cinstar® is available directly from stock in sizes M3 through M8, made of A2 stainless steel, with a low-profile head or a flat-countersunk head.
Do I need any special tools for installation and removal?
Yes. Cinstar® can only be installed or removed using the corresponding SecuFast Cinstar® bit. In the Benelux, this bit is available exclusively through SecuFast (Archey). This allows you to control who has access to the installed components.
Do safety screws meet CE requirements for machine safety?
Security screws are not a CE requirement in and of themselves, but they do contribute to the design of fixed screens in accordance with ISO 14120. That standard requires that screens can only be opened with a tool. A special tool that is not available over the counter demonstrably increases that level of security.
What are some typical applications in mechanical engineering?
Control cabinets, switch panels, protective covers for moving parts, sensor and encoder housings, and service doors for maintenance personnel.
Cinstar® security screws from SecuFast
SecuFast specializes in security fasteners and supplies Cinstar® directly from stock in a variety of sizes and styles. In the Benelux, this ensures fast delivery, the right tools, and technical advice—all from a single partner.
Next step: View the complete Cinstar® product range or request technical advice for your specific application.
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At Archey, we are challenged multiple times on issues where our high-quality fasteners play a decisive role. We prefer to share those challenges with the whole world.
February 24, 2024








