Tamper-Resistant Security Nuts
Security nuts protect the nut side of a bolted joint. Tri-Groove nuts use an external grooved profile that requires a matching socket for normal installation and authorized removal. Break-away nuts use an installation section designed to separate during tightening, leaving a reduced-grip security profile. The two styles offer different levels of serviceability — the right choice depends on whether future authorized removal is expected.
Tri-Groove vs. break-away security nuts
Tri-Groove nuts
The nut uses external grooves around a rounded security profile. A matching Tri-Groove socket fits over the nut and engages the grooves, permitting both installation and authorized removal. The rounded exterior limits the useful gripping surfaces available to common pliers and wrenches. Tool access and socket clearance around the nut need to be considered at the design stage.
Break-away nuts
A break-away nut includes an installation section intended to be tightened with a conventional compatible tool. At the designed separation point, the installation section breaks away, leaving the remaining security portion with fewer ordinary tool-engagement surfaces. The nut is intended for installations where routine removal isn't expected — future removal may require a specialized or destructive method and a replacement nut, so exact installation requirements should be confirmed for the specific part.
Both styles are tamper-resistant, not removal-proof, and they are not interchangeable — the right one depends on whether the joint needs to be serviced again.
- Tri-Groove Nuts
- Break-Away Nuts
- Matching Tri-Groove Sockets
Ranges shown represent what we generally offer across this category. Not every size is available in every style or material. Exact thread requirements, dimensions, availability, minimum quantities, tooling, and possible custom requirements should be confirmed with Screw & Supply.
How to specify a tamper-resistant security nut
The nut thread must match the mating bolt or stud in diameter, pitch, and thread system. Consider a Tri-Groove nut where authorized removal with a matching socket may be required, and a break-away nut where routine removal isn't expected. Clearance around a Tri-Groove nut is needed for the external socket, and a removal-and-replacement plan should be considered before selecting a break-away nut. Confirm the following, and include as much as possible on any RFQ:
- StyleTri-Groove or break-away
- Thread systemInch or metric
- Thread diameterNominal thread diameter
- Thread pitchMatched to the mating bolt or stud
- Mating bolt or studWhat the nut threads onto
- Nut dimensions & clearanceAvailable space around the joint
- MaterialZinc alloy or stainless steel
- Installation methodTooling and access during install
- Authorized removal / service needsWhether the joint may need to be reopened
- Matching Tri-Groove socketWhen applicable
- QuantityFor stock pricing or a custom production run
- Drawing or printRequired for any custom configuration
This list is a starting point for a quote request, not a substitute for engineering review of your specific application. Material compatibility and installation environment should also be reviewed.
Plan the tooling and future service method
Tri-Groove nuts require a correctly sized matching security socket that fits over the outside of the nut and engages the grooves — socket size must match the nut series, and clearance must be available around the nut for the socket body. Break-away nuts use an installation section designed to separate during tightening, so any break-away installation should include a plan for future removal and replacement. Confirm installation tooling and removal requirements before ordering; not every socket fits every Tri-Groove nut.
Tri-Groove Sockets →
Matching sockets sized to our Tri-Groove nut series for installation and authorized removal.
Drive Guide →
Compare Tri-Groove against our other security drive systems to confirm it fits your job.
Request a Quote →
Tell us your joint, style, and service plans so we can confirm the right nut and tooling.
Where security nuts protect the joint
Security nuts are considered when the nut side of a bolted assembly is accessible and casual removal or theft should be discouraged, including anti-theft mounting on exposed hardware.
- Utility & Infrastructure →
Secures guardrail, fencing, and outdoor utility fixtures.
- Transit, Rail & Signage →
Holds transit hardware and signage exposed to public contact.
- Detention & Institutional →
Used on institutional fixtures requiring controlled access.
- Machinery Guarding & Panels →
Secures guards and equipment panels against casual removal.
- Amusement & Fitness Equipment →
Used on public-use equipment where tampering is a concern.
- Public Restrooms & Partitions →
Secures restroom fixtures and partitions in public spaces.
Standard configurations and custom specials
We can help identify a standard security nut that fits your application, or review requirements for a custom special. For a custom inquiry, provide a drawing or print with style (Tri-Groove or break-away), inch or metric thread, diameter, thread pitch, mating bolt or stud information, nut dimensions, material, quantity, application details, installation environment, tooling requirements, removal or service requirements, and any inspection or documentation requirements. We'll review what you send and follow up on feasibility.
Common questions
- What types of tamper-resistant security nuts are available?
- We offer two documented styles: Tri-Groove nuts and break-away nuts. They use different security principles and are not interchangeable.
- What is the difference between a Tri-Groove nut and a break-away nut?
- A Tri-Groove nut has an external grooved profile installed and removed with a compatible matching socket. A break-away nut has an installation section designed to separate during tightening, leaving a reduced-grip security profile not intended for routine removal.
- Can a Tri-Groove nut be removed for authorized service?
- Yes, with a compatible matching Tri-Groove socket. The socket fits over the nut and engages the grooves for both installation and authorized removal.
- How is a break-away security nut installed?
- A break-away nut is tightened with a conventional compatible tool on its installation section. At the designed separation point, that section breaks away, leaving the security portion in place. It is generally selected where routine removal is not expected.
- Which security-nut sizes and materials are offered?
- Inch sizes generally range from #6 through 5/8 inch and metric sizes from M4 through M10, in zinc alloy and stainless steel. Exact availability varies and should be confirmed when requesting a quote.
- Can Screw & Supply provide matching sockets or review custom requirements?
- Yes. We can help confirm socket compatibility and review custom fastener requirements. Send your details through a quote request and we will follow up.