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Snake Eye and Pig Nose Security Screws - What’s the Difference


When talking about fixings and fastenings there is an awful lot of technical terminology and jargon we all need to be aware of. In this post we take a close look at just one of our popular ranges of tamper-proof security fastenings - Snake Eye Security Screws.

The terms Snake Eye security screws, Pig Nose security screws, two-hole screws and twin-hole screws are all interchangeable. There is absolutely no difference between a Pig Nose and Snake Eye security screw. They are both simply alternative names used to describe the 2-Hole Security Screw range as supplied from our Insight Security online store.

The ‘pig nose’ and ‘snake eye’ descriptions refer to the appearance of these useful fastenings. Instead of having a slot or cross head that mates with an appropriate screwdriver these screws simply have two holes that resemble a pair of snake’s eyes or a pig’s nose. This attractive screw head design requires a unique, two-pin screwdriver to install and remove the screws making them more secure than standard screw fastenings.

Designed for low to medium torque applications, they are available in a variety of styles and lengths from stock, including Two Hole AB Type Self Tapping Security Screws and Metric Machine Screws and Bolts. We also supply bespoke manufactured security fastenings to meet specific requirements.

pig nose security screw range
Pig Nose or Snake Eye Security Screw Range


Attractive Appearance

The appearance and versatility of Snake Eye or Pig Nose security screws makes them a favourite with architects and designers around the world. And since the stock range is manufactured from high quality A2 stainless steel, they are suitable for use in almost any environment, indoor and outdoor.

snake eye screws security post
2 Hole Security Screws Supporting Stainless Steel Post


You can see these two-hole anti tamper security screws in many public applications. For example, they are often used to secure glass panels to stair rails in airports and you will also see this form of fastening commonly used on public transport, in bus shelters and they are often chosen to fix signage in place. When you start to notice where two-hole screws are used it quickly becomes apparent how ubiquitous they are.

pig nose security screws fixing door entry panel
Pig Nose Security Screws Fastening a Door Entry Panel


This form of security fastening is also the natural choice for fixing decorative panels in place, as can be seen at some of London’s Underground Tube Stations. They are ideal for securing a wide range of panels, plates and materials which is why they are popular with Museums and Art Galleries. They are also widely used by the War Graves Commission, retail organisations and shopping malls as well as CCTV and Access Control System product installers.

twin hole fastenings on the london underground
Decorative Panels at London Underground Station Fixed in Place with Two-Hole Fastenings


Two-Hole Security Screw Head Types

Snake Eye or Pig Nose two hole security screws are available in a wide range of head styles to suit a multitude of applications. They include: pan head, countersunk and raised countersunk.

2 hole security fastenings in use
2 Hole Security Fastenings Supporting Glass Signage


The stock two-hole security screw product range includes self-tapping screws and machine screws with a choice of lengths and head styles. While bespoke manufactured fastenings range from Panel Fixings, to Barrel Nuts and Bolts as well as other specialist items such as Grub Screws.

bespoke 2 hole security fastening
Attractive Bespoke 2 Hole Security Fastening


For example, bespoke anti tamper two hole fastenings were manufactured for a busy international airport to include rubber buffer rings which protected the fastened glass panels when the bolts were installed and tightened.

 Another great application example is the use of Raised Countersunk two hole security machine screws to fix 13A electrical outlet socket cover plates in position, instead of the standard screws supplied. This simple change improves safety by preventing children and others from accessing or tampering with the potentially dangerous electrical outlet.

Twin Hole Security Screw Driver Sizes

As noted, to install or remove two hole security screws an appropriate screwdriver tool is needed. It`s important to be aware that different sizes of driver tools are needed to match the dimensions of the fastenings. For example, an M5 metric gauge countersunk two-hole machine screw requires a TH6 driver size while the M6 gauge fastenings require a TH8 driver size. Options include either an appropriately sized one piece two-hole screw driver or suitable screwdriver bits.

The fact that these fastenings require this specialist form of driver is what makes them so secure. Standard slotted or crosshead fastenings can potentially be undone using nothing more than the edge of a coin, whereas the clever two hole design can’t be tampered with so easily. 

If you have any questions about security fastenings or if you have any special requirements remember that we are here to help. Give us a call on 01273 475500 and we’ll provide you with free, expert advice.

This message was added on Thursday 6th January 2022


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