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Choosing the Right Padlock - Standard to High Security Lock Types and Their Applications

Article Topics:

  1. Parts of a Padlock
  2. Padlock Types
  3. Different Padlock Materials
  4. What to Look for when Choosing a Padlock


Padlocks provide a simple and effective way to protect valuables against theft nand property from unauthorised entry. They are relatively low cost and convenient to use, indoors and outdoors, small or large, from gym locker to garden gate or shed, to extra security for exterior domestic doors, storage units or for higher security commercial applications.

It’s important to choose a secure padlock that's appropriate for your needs, in terms of lock type and material.  

In this article we'll explore the world of padlocks, from high security locks to practical lower price options.

Let's begin by identifying the three main elements of a padlock.

Parts of a Padlock

To help choose the right padlock, it's useful to know its constituent parts: the body, the shackle, and the locking mechanism.

The Body

The padlock body protects the locking mechanism from attack or tampering. The body can be made from laminated steel, solid brass, hardened steel or similar materials.

Some padlocks are weather-resistant and are covered with rubber for protection against the elements when used outdoors. Others use materials that are themselves corrosion resistant.

The Shackle

The shackle is commonly the U-shaped part of a padlock. Sometimes it can be straight, depending on the padlock type. The shackle inserts into the lock mechanism, and is released using a key or numeric combination.

The Locking Mechanism

Padlocks most commonly use pin tumbler locking mechanisms. For higher security, consider lever tumbler or disc tumbler options.

Pin Tumbler

Pin tumbler padlock mechanisms consist of a series of pins of varying lengths within a cylindrical housing. The correct key aligns the pins at the shear line, allowing the lock to be turned to release the shackle.

Pin tumbler pad lock - exposed locking mechanism

Image Credit: Engineering Mindset

Lever Tumbler

Lever tumbler locks use a set of levers inside the lock mechanism. The correct key lifts the levers to specific heights to release the shackle.

The lever tumbler mechanism type offers higher resistance to lock picking attempts due to the complexity of lifting multiple levers simultaneously to their release positions.

Disc Tumbler

As the name suggests, disc tumbler locks use rotating discs. The correct key has notches that engage with the discs, aligning them in such a way so that the shackle is released.

Disc tumbler locks offer a high level of security due to the complexity of disc rotation compared with pins or levers.

Padlock Types

There are five distinctive padlock types:

  1. Open shackle
  2. Long shackle
  3. Closed shackle
  4. Straight shackle
  5. Shrouded shackle

Open Shackle

The open shackle padlock is the most common type. It's suitable for lower and moderate protection. Easy access through chain links, bolts, or hasp and staple latches, makes it versatile and easy to use.

Long Shackle

For better versatility, long shackle padlocks can cover a greater area for when a shorter shackle is too restrictive.

However, keep in mind that the longer the shackle, the more vulnerable it will be to bolt cutters and saws.

Lower price brass long shackle padlock

Closed Shackle

Closed shackle padlocks can offer better security compared with open shackle, as the shackle is less exposed. This makes it more difficult for would-be thieves to compromise the padlock.

Closed shackle padlock - robust security

Shrouded Shackle

Discus padlocks, or disc padlocks, are known for their excellent protection. Made with a type of closed shackle known as a shrouded shackle, they offer greater protection against bolt cutter and saw attack as the shackle is concealed within the padlock body.

They also offer higher corrosion resistance and anti-pick features that make them ideal (and popular) for outdoor use.

Disc lock - offering exceptional value - with robust security

Straight Shackle

Heavy duty straight shackle padlocks are better suited for higher security and commercial applications, for premises doors and roller shutters, containers, gates, barriers or thicker chains.

High security locks - high security padlock

Keying Options

If you use more than two padlocks, then keeping multiple keys might feel like a headache. 'Keyed alike' padlocks are sold as a set sharing the same key. This eliminates the need for a key-to-lock ID system, such as numbering, making life much easier where multiple padlocks are needed.  

Combination Padlocks

Combination padlocks offer a flexible alternative as you don't need to carry a key around or risk losing it.

Also, not needing a key, a combination padlock means that access can be given to multiple people without getting new keys cut. This could be beneficial in certain commercial settings.

Padlock Materials

Choosing the Appropriate Material

The material that a padlock is made from plays an important role in choosing the right padlock for your needs. Different materials have differing characteristics. Let’s take a look at some of the more common metals used, starting with laminated steel.

Laminated Steel

Laminated steel padlocks are constructed from layers of steel plates that are stacked and fused together. Each plate is punched, bent, and riveted, creating a tough and durable lock body.

They offer strength and durability, and often feature a corrosion resistant coating for outdoor use.

Lower price - laminated steel padlock with chain


Brass is perhaps the most common padlock material. Available in a large range of shapes and sizes, brass padlocks are highly corrosion resistant and are often priced accessibly. They have great functionality, suitable for low and medium level security applications, such as lockers, cabinets, luggage, doors and gates.

Small brass lock with key - typical of major padlock manufacturers

Hardened Steel

Hardened steel padlocks are manufactured using a heat treatment process that strengthens the steel, making it resistant to cutting, drilling, and other forms of tampering. Hardened steel padlocks are better suited for higher security and commercial uses.

High security padlocks -

Weather Resistant

Weather resistant, or ‘weather proof’, padlocks are made from thermo-plastic sheathed brass, stainless steel, hardened steel, or even aluminium. If you choose a weather resistant padlock for a garden gate or shed door, make sure you know what material it is.

Lower price - weatherproof open shackle padlock

What to Look for when Choosing a Padlock

Check the Security Level

Most of the time, padlock manufacturers will offer a security rating guide. However, high-security padlocks need to have two reliable standards ratings: 'CEN' and 'sold secure'.

Sold Secure

The ‘sold secure’ rating system is divided into three categories: gold, silver, and bronze. Each rating represents the levels of aggression a padlock must withstand, with gold being the highest security rating.

Central European Norm (CEN)

A padlock's CEN grade is a European standard and can be categorised from CEN level 3 to CEN level 6. The rating is the same as sold secure, with CEN 6 being the highest.

For a comprehensive guide to padlock security ratings, check out the What are the Most Secure Types of Padlock article.

Higher price product - high security padlock

Check the Shackle Size

Another important aspect when buying a padlock is the shackle's size. A diameter of 7mm will only handle low-security needs.

A shackle with 8mm to 10 mm diameter is better for medium security requirements, while anything above 10mm is best for high-security purposes.

Heavy duty padlock on gate - for higher security application

Other Considerations

Here’s a quick check list of things to consider when choosing your padlock:

  • Will the padlock be used outdoors or indoors
  • Think whether a key or a combination padlock will suit your needs
  • Measure the inside space of the ring where the padlock will be installed — the shackle must be long enough
  • If you need multiple padlocks, consider keyed alike
  • Weigh how much you want to spend against the security level you want — if you need high-security, you will need to spend more on the right padlock for the job

Final Thoughts

Padlocks offer a convenient and cost effective way to secure your property. Whether it's for standard security in domestic situations or high security for outdoor or commercial use, there are a wide variety of padlocks to choose from to protect your home or business.

Hopefully this article will have provided you with everything you want to know about padlocks, and will have helped you choose the right one for your security needs.

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A variety of secure padlocks - locks