Certain special applications call for using fasteners that cannot be turned or removed by normal tools, adding a degree of protection to the contents of containers, the integrity of fabricated structures, the strength of critical assemblies, and so on.  These special hardware pieces are known as Tamper-Proof Fasteners, and in this article, we’ll take a look at common styles and options available for your sensitive applications.   

Tamper-Proof Fasteners Overview

Right off the bat, let’s address the term ‘tamper-proof’.  A fastener is considered tamper-proof if it cannot be adjusted or removed by unintended parties, by definition, but we find that this usually has more to do with the determination of the manipulator than the resilience of the fastener.  Any diligent person with enough time, energy, and blunt objects can tamper with a fastener to the degree that it fails, or at least is damaged beyond reuse.  Tamper-‘proof’ is in most cases therefore a marketing term, and fasteners should instead be more accurately considered tamper-‘resistant’.  We’ll use this term for the rest of the article.    

Tamper-resistant fasteners generally target one or more of three goals:

  • Resists Removal – such as with a locked door on a toolbox that could be opened by removing the hinge screws
  • Resists Tightening / Untightening – such as where tightening a bearing block screw would change the friction in the bearing, altering rotation to an unsafe degree
  • Resists Vandalism – such as with the face screws on an ATM machine where attempts to unscrew during vandalism will complicate future maintenance and service disassemble

The main feature that makes a fastener tamper-resistant is the drive type.  As such, tamper-resistant hardware is available in nearly all common styles, specifications, profiles, head types, and materials as standard hardware, with only the drive design being unique. 

When selecting tamper-resistant hardware, consider your application first and foremost: what of the above three goals are you looking to achieve, and what degree of protection are you looking to invest in?  We categorize tamper-resistant fasteners into three categories, each one providing a different balance of cost to tamper resistance. 

Uncommon Drive Styles

Uncommon Drive styles – the first tier of tamper resistance is found in this category, which simply looks to use a drive style on the head of the fastener that requires a relatively uncommon tool for your general vandal or layperson to carry with them.  Instead of Phillips or Flat screw heads, we find Torx, square, and other uncommon drives here.  These tools are commercially available to anyone from your local hardware store.  The level of protection provided is essential in making the bet that a vandal will not have this tool readily available.   

Examples of Uncommon Drive styles:

  • Torx Drive – also known as a ‘star drive’, Torx drives use a 6-point star-shaped pattern.  Known in ISO standards as a ‘hexalobular internal’ drive. 
  • Hex / Allen Drive – another internal hexagonal shape drive, this one with flat sides instead of the Torx’s star-shaped sides.  
  • Square Drive – a four-sided internal drive in the shape of a square. 

Do you have a tamper-resistant fastening application but are unsure of which specialty fastener might be best to use?  E&T Fasteners offers expert support and product selection between the above options and more!  Contact us to discuss your application, or to see our standard fastener offerings, visit our product selection here

Special Drive Styles

The next tier of tamper resistance is found by fasteners having Special Drive styles – that is, drive tool designs that are commercially available to anyone, but that are not usually found at local stores and need to be ordered.  These fasteners increase the unlikelihood that a common vandal will have the special tool available, granting a further degree of protection to your property.  It should be noted however that determined vandals will usually increase their level of force here, employing drills or grinders to remove the fastener, bypassing the special drive limitation entirely.  Because of this, consider purchasing these fasteners in hardened materials and color-matching finishes, limiting their visibility and the speed that they can be cut. 

Examples of Special Drive styles:

  • Spanner Drive – utilizes two small indentations on the head that use a flat tool with matching drive beads to engage the fastener.
  • Multi-Lobe Drive – similar to a common Torx drive that uses 6 lobes, several less-common options using various lobe quantities are available, such as 4 lobe (quadlobular) or 5 lobe (pentalobular).
  • One-Way Drive – using a rounded profile with flat, drivable surfaces facing only in the tightening direction, this drive style has no surface that allows direct unfastening.
  • Tri-Wing Drive – a unique but commercially available three-sided drive that requires a special matching tool to drive. 

Proprietary Drive Styles  

The highest tier of tamper resistance comes in the form of Proprietary Drive style fasteners.  In this category, fasteners and drive tools are custom manufactured by specialty tool suppliers, and the sale of these components is strictly limited to known, documented purchasers.  Vandals would very likely have no access to the tools needed to properly manipulate these fasteners.  However, this does mean that determined vandals will jump straight to power tools to remove or cut around these fasteners, so careful thought should go into an investment in these pricey options. 

Examples of Proprietary Drive styles:

  • Bryce Key-Rex Custom Pattern Drive – manufactured by Bryce Fasteners, the Key-Rex drive is a totally custom, purchaser-specific pair of hardware and tooling that is marketed as a ‘fingerprint-level unique drive’ specially made for each order.  No one but the ordering party will have the appropriate pattern tool to manipulate these fasteners.  
  • Tanner Lock-Out Drive – manufactured by Tanner Bolt Co, these drives are a proprietary 4-pin design with a center block-out stud that resists the use of any tools other than their special drive keys.
  • Tanner Trident Drive – also made by Tanner Bolt Co, these drives are a unique spin on a trilobular design, again using only their special drive tool.
  • TamperProof Trilobular Drive – manufactured by TamperProof Screw Co, these drives use a very unique 3-lobe design with convex faces between vertices, unlike standard 3-lobes that use concave faces. 

E&T Fasteners is here to help you navigate fastener and accessory options.  Price quotes, availability, lead times, delivery confirmations, unique application suggestions – whatever your need, we’re here to take your call or email.  For support and advice from our fully trained staff, speak with an E&T sales representative today. 

About E&T Fasteners

With sales and support teams spanning the Continental US, E&T Fasteners is here to serve your hardware, fastening, and component needs both domestically and internationally.  We are a stocking distributor of metallic, plastic, and exotic alloy fasteners, backed by our technical staff directly experienced in your unique applications.  We can assist your specifying and selection efforts, providing engineered solutions, record-fast lead times, and stellar customer service from quote through delivery.  Please let us know how we can help!