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Security Tri Head Bolt (Triangle Head Bolt)

Tamper resistant Tri Head security bolts / screws

Tri head (triangle head) security bolts are 2 way reusable security fixings with a deep triangle head design and flange ideal for security applications that have a recess or channel. Tri head bolts / screws are also known as security din 22424 screws. Their unique head design has led to their use in applications in a recess, e.g. for securing access panels in lamp posts, wheelie bins, telephone and electrical switching cabinets etc.
These tamper resistant bolts offer economical low level protection in public areas.

Available in A2 stainless steel and in M8 thread off the shelf with other diameters, lengths and materials (e.g. zinc plated steel) available to order (grade 5.8 and 8.8 screws and nuts available to order from M5 – M20).

Thread / Length (mm) 20 30 40 50


Special Triangular Head Design
Deep Triangular Head and Flange
Requires Special Key Wrench
Tamper Resistant Tri Head (Triangle Head) Security Screws

Tamper resistant Tri Head Security Bolts (triangle head security screws)

The Tri Head Security Bolt / Screw has a unique deep triangular head with a flange that requiring a special key wrench to insert and remove. This unique feature renders the tamper resistant Tri Heads security screw tamper proof, reducing the risk of vandals or intruders tampering with or undoing the screws.

This security bolt is suitable for higher torque applications and is a 2 way reusable fixing making it the ideal security fastener for applications where maintenance is required.

The Tri Head drive is designed to use a key wrench and hence reduce and resist cam-out, which can occur more frequently in other drive types. The deep triangle style head makes this the perfect security screw in applications with a recess or channel such as lamp post and telephone switching cabinets.

Tamper resistant Tri Head security screws offer a medium security resistance against vandals and thieves at a relatively low cost, proving an economic and secure equilibrium. Within the industry Tri Head security screws are also referred to by other names including Triangle Head Screw. Security Din 22424, Security Lamp Post Screws and Security Recess Screws.

The head design on this security fastener specifically reduces cam-out and is fastened using its matching security key wrench. The head also features a flange negating the need for a washer to be used.

Note: Special Tri Head Security Screws can be made to order including small volume manufacture, modifications and custom parts to drawings.

Tamper Resistant Tri Head security screws can be used with the matching Tri Head security nut (Din 22425) or alternative security Wave Nuts, Shear Nuts, Kinmar Reusable Nuts, Kinmar Permanent Nuts, 4-Hole Nuts or Pin Torx Barrel Nuts for added security.

For more information and technical data regarding tamper resistant Tri Head security products please call our sales team.

Tri head screw technical drawing

M8 X (20, 30, 40mm) 13.7 8.5 6.5 1.5
M8 X 50mm 17.0 8.5 6.0 2.0

*For guidance purposes only

Ultra Drive Self Tapping Security Screw