Exploring the Different Types of Padlock

There is a host of padlocks on the market and it can be difficult to know which one to choose. Sometimes an insurance company might require a certain type or security level. Or perhaps you just want the peace of mind that your shed, garage or bike has been reasonably secured. Our guide gives you a basic understanding of the different types of padlock to help you make the right choice.

Types of Padlock

When it comes to choosing a padlock you may find the choice a little overwhelming to start. There are all sorts of shapes, sizes and types. Some are designed for high security, others have weather protection and are better used outdoors.

There are four main types of padlock:

• Closed shackle padlocks
• Straight shackle padlocks (or roller shutter padlock)
• Discus or circular padlocks
• Long shackle padlocks

Before we look at each type in more detail, it’s worth getting some basics on the parts of a padlock and how a padlock works.

The Basic Workings of a Padlock

The most obvious part of a padlock is the U-shaped shackle which sits inside the padlock’s body. When you put your key into the lock barrel (also known as a tumbler) you turn the barrel and the shackle pops out at one end, allowing you to move the shackle.

Inside the lock’s casing there is a locking mechanism which fixes into notches on the shackle preventing the shackle being pulled upwards when it is locked.

Inside the casing are a number of spring-loaded pins that slot into holes in the barrel stopping it from being turned without the key. Each pin is a different height but matches the key’s profile. When you put your key into the padlock the pins are moved to align in such a way that the barrel can be turned. As the barrel rotates it releases the locking mechanism that slots into the shackle’s notches.

The security rating of a padlock comes from a combination of how hard the material is (padlocks may be made from brass or hardened steel for example), the number of pins and how accessible the shackle is. Insurers have certain grades of security requirements and of course you can’t overlook that your padlock is only one part of it…

… your fittings are as important as the lock itself. If your hasp and staple (those bits the shackle goes through) are vulnerable a good lock won’t matter.

Closed Shackle Padlocks

With a closed shackle design, the shackle is better protected by the casing of the padlock. A traditional padlock might have a squarish-shaped body with the u-shaped shackle sitting outside the case above it. But with a closed shackle padlock the body covers more of the shackle making it harder to access with bolt cutters or a hacksaw.

There might be very little of the shackle on view and it’s a popular minimum request from insurance companies.

The advantages are the extra security that comes with a protected shackle, but that means there’s less shackle available to be able to fit it through the hole or the locking hardware in place. So it’s important to get your measurements right.

The Straight Shackle Padlock (Shutter Padlock)

Instead of a u-shape a padlock might have a straight bar. These are often used and a minimum requirement for insurers when it comes to securing metal shutters. The shackle is protected and the straight bar makes them a perfect fit for shop roller shutters.

But that doesn’t mean that they can only be used on shop shutters. These are high security padlocks and versatile in many situations. They are easy to fit and so are often often used in other commercial settings such as to secure containers or lorry doors.  By design the shackle is guarded so makes these closed shackle padlocks too.

The Discus, Circular or Round Shackle Padlocks

A common variety of closed shackle padlock is the circular or discus padlock. The shackle goes round the circumference of the padlock and the key is in the centre. As there are no springs drilling the lock or damaging the barrel in any way won’t force the lock. It makes these incredibly secure and thus popular.

The body isn’t solid like with other padlocks, instead the mechanism sits inside two circular cases that form the disc. However, as cheaper models become available, some of these lesser quality locks have been hammered, causing the casing to fall apart, exposing the mechanism. This won’t happen with high quality models.

German manufacturer ABUS further added a hardened steel disc into the casing of their discus padlocks to prevent attack from crushing, and they are considered the leaders in the manufacture of round padlocks.

Combination and Long Shackle Padlocks

Long shackle padlocks are the same as traditional padlocks but the u-shaped shackle is extended to make placing the padlock more convenient. The convenience comes at a price though. The shackle is the weakest point of a padlock and increasing the shackle reduces the security potential of the padlock. It gives a potential padlock attacker more room to use their tools.

Compared to a traditional padlock combination locks are far less secure and most insurance companies won’t cover good protected by them. If you’ve been to a gym and used their combination padlocks you’ll know they can be reset and the code changed. This makes them vulnerable. Some manufacturers introduced a system whereby a key was needed to rest the code. What’s more a person could systematically go through the number sequence if they wanted to get the lock open. A three digit code would only take a maximum of 40 minutes to crack. They really aren’t suitable for security in remote areas.

They are however handy in low risk areas if more than one person needs access to an area and keys aren’t practical.

Final Thoughts

A good padlock is worth its price when it comes to security and peace of mind. But you also don’t need to go overboard. A school cupboard might only need a combination padlock to keep pranksters out and allows teachers easy access. But a commercial container would need a highly secure top level closed shackle padlock to reduce the risk of theft and satisfy insurers. To keep your shed secure you’d need something secure that is perhaps laminated but definitely won’t corrode easily.

And don’t forget… your fittings need to be secure too.