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Lock Blog

A resource for consumers, locksmiths, and security professionals

Inside Padlocks: How Padlocks Are Made

by Taylor May 2, 2022

You’ve probably depended greatly on padlocks at some point in your life. Affordable and portable, padlocks are an ingenious invention, useful for average security or even secure expressions of love. Overall, they’re indispensable. The history of padlocks is extensive for a reason.

But what’s actually inside of padlocks? It’s a little enigmatic, isn’t it? They’re essentially these mysterious metal boxes that can’t be easily broken open. How do they work? And how are they built?

To answer this question, we need to look at how padlocks are manufactured and what goes into making them. We need to look at what’s inside of padlocks, what parts go into the process, and how they work.

So what’s inside of padlocks?

  1. How Padlocks Are Manufactured
  2. What’s Inside Of Padlocks?
  3. How Padlocks Work

How Padlocks Are Manufactured

Padlocks are often made in multiple locations by multiple factories. The process of making a padlock is a long one.

Manufacturing The Body

The most common padlock, the Master laminated lock, has a body made of several sheets of metal stacked on top of each other that are laminated together. This lamination is how bank vaults are made. It helps reinforce the metal.

Even when a padlock isn’t laminated, they tend to look similar on the inside. These pieces of stacked metal make the inside of the body stronger so that the lock can’t be broken easily.

The actual metal used changes based on the cheapness of the lock. Most use brass because it’s effective for environmental resistance, or aluminum to the same effect. The problem is that these two metals are relatively soft. More high-security padlocks go for stainless steel or zinc. The inside of padlocks must be inaccessible, so the metal generally should be strong.

After the metal is shaped, caps are then riveted into the lock body, and the body is complete.

Manufacturing The Shackle

Steel rods are cut by a machine to allow them to fit into the holes on top of the lock body. They’re then bent by a bending robot and tempered for strength.

Divots are then cut into the bottom of the inside of the shackle. These divots allow the locking mechanism to work as it should. Eventually, once everything is completed, latches will catch on the holes and prevent the lock from being opened.

Manufacturing The Mechanism

This is where you make everything that goes inside of padlocks. Some padlocks have ball bearings put in at this stage. Without these bearings, the padlock can be shimmed open by putting a shim at the bottom of the shackle and forcing the lock open. With these ball bearings, the shim is blocked.

A cylindrical case is put inside of padlocks. This will prepare the padlock for the lock cylinder.

Machines put the pieces of the cylinder together. This includes taking a plug, loading it with pins and springs, and installing a casing around it. The loading of the pins is random unless it is a keyed alike padlock, in which case there are specified pins put in there.

Finishing Up

Finally, a key is cut to match the pins inside the cylinder. A worker takes empty bodies and places the finished cylinder inside of padlocks. They also sort the matching keys and ensure they go with the correct padlock. A spring is placed at the bottom, and a casing closes the padlock up.

At the end of the process, the padlock is usually tested to ensure everything is working as it should. The padlocks are tested both for the ease of use and strength of the lock itself. After that, it’s ready to be sold.

What’s Inside of Padlocks?

There’s actually a lot inside of padlocks.

First is the plug, which is where the key is inserted. This looks like a cylinder with a slot for a key to fit through. There are several parts to a plug, all relating to the unlocking of a lock.

Next are the pins, which are little bullet-shaped metal pieces that sit at the top of the plug. There are generally six to twelve pins in any given lock, stacked in groups consisting of two. The pin at the top of the stack is called the driver pin, and the bottom one is called the key pin.

There’s also a single extra pin called a security pin. This pin prevents the plug from being taken out.

The pins are being held in place by springs to prevent them from loosely sliding around inside the plug.

Next are the latches. These are located behind the plug and are held together by two springs.

Finally, there’s the shackle itself. It’s actually asymmetrical. One side reaches the bottom of the padlock, and the other side is short enough to pull out of the hole when the padlock is unlocked. Unless you are dealing with a full-release shackle that comes out entirely when opened.

Unusual Padlocks

There are some exceptions to this. The above describes the typical pin tumbler padlocks, but there’s a large variety of other types of padlocks, each with its own unlocking mechanisms.

The most common alternate padlock is the combination lock, which is a lot like a disk detainer lock. These are made up of several rotating disks with notches underneath the correct numbers or letters.

Another semi-common padlock type is the warded padlock. These have no pins. They instead have unique shapes cut into the plug that only the right-shaped key (or a skeleton key) can fit through.

Some padlocks have extra long shackles that can be fully removed from the padlock whenever it’s locked or unlocked.

Some use electronics to unlock. These generally have batteries, Bluetooth scanning devices, or fingerprint scanners, depending on how the electronic lock works.

As a whole, there are a large variety of strange locks out there. There are too many to list here.

How Padlocks Actually Work

So that’s all well and good, but how does all of it fit together? What are all these pieces doing inside of padlocks?

Pin Tumbler Locks

Since pin tumbler locks are by far the most common, we’ll go over how exactly those work over other types of locks.

The key is inserted into the plug. As discussed before, the plug is full of key pins and driver pins. The bottom pins are called the “key” pins because they’re the ones the keys are touching after they’re put inside padlocks.

An important thing to note is that all of the key pins are of a different size from stack to stack. You’ll see why later.

When the key is inserted, it pushes the key pins upward. This causes the driver pins to also move upward, which causes them to be pushed downward by the spring they’re now tensioned against.

The pins should be in a specific configuration now. This configuration results in the top of the key pins lining up with each other. Because they’re different sizes, the key needs to push them up at different lengths. A key that was shaped differently wouldn’t be able to push them up at the correct length.

Once the pins are lined up, all of the key pins should be inside the plug, while the driver pins are above the plug. Without the key, the driver pins will be partway in both, blocking the plug and preventing it from turning. With the correct key, however, the plug can now turn.

That’s the basics of how a pin tumbler lock works.

Shackles

So once the key turns, what opens the padlock? Let’s look at what causes the release of the shackle.

The plug has a cam (a tiny little metal square) at the back of it. As the key rotates the plug, the cam rotates. Its edges catch on two hook-like latches and pulls them towards each other.

The other ends of these latches are inside the little divots cut into the shackle. When the hooks are pulled closer, they leave the divots, allowing the shackle to move freely.

That’s the basics of what’s located inside of padlocks. Without all these parts, they wouldn’t work. The inside of padlocks is pretty complex, as it turns out.

FAQs

How are padlocks made?

The individual parts of a padlock are made in a factory, often multiple factories, and put together by hand. First, the outer casing is made. Then, the cylinder plug and other locking parts are made. Then the shackle is bent into the right shape.

Pins are put inside the plug, and a key that corresponds with the specific pins is cut. The key and plug are kept together, and a person working at the factory puts these plugs inside of padlock bodies, keeping the right key with the right padlock.

What are padlocks made of? 

This depends on the padlock. If you’re looking to buy a cheap lock, it’ll probably be brass. Most use some kind of stainless steel instead. Sometimes, you can find padlocks made of aluminum, which is as secure as brass. And some of the high-end padlocks are made of hardened steel.

You can also find zamak and zinc in combination locks. There are sometimes nylon washers inside of padlocks that need them.

Shackles are made of similar materials. They also use brass, aluminum, and steel. They can also have shrouds that sound the steel, which reinforces them.

What are Master Locks made of?

The packaging of your specific master lock should say. Master locks are often cheaply made, so they tend to use brass and aluminum. Some of the better master locks use stainless steel, however. The inside of padlocks consists of similar metals.

What’s on the inside of a Master padlock?

Master padlocks aren’t much different from other padlocks or any given pin tumbler lock, like the kind inside doors. The inside of padlocks like these is pretty typical.

They have plugs where the key is placed. Inside these plugs are pins that the key interacts with. When the key is correct, the pins line up and the plug can be turned. When it is turned, latches in the back unhook the shackle. This allows the padlock to be opened.

Conclusion

There’s something kind of enticing about padlocks. They’re strong metal boxes that do a lot of work for you. You’ve probably used them many times, as locks for storage units to locker locks and beyond. It’s hard to not wonder what’s inside of padlocks and how they work.

Padlocks are carefully crafted in factories. They come with multiple layers of protection to guarantee they can’t be broken easily by people trying to break into secure places. The lock mechanism itself is also carefully crafted in these factories, and everything is put together with the correct and randomized keys and pins.

There are a lot of different parts that go into this process. If you were to completely gut a padlock, you’d find all kinds of specific parts that must go together in a particular order. You have pins that interact with keys, bits that hold the shackle, and other vital objects in the locking mechanism. And these parts can change a lot depending on the type of padlock you have!

Each of them plays a role in ensuring the locking mechanism works like it’s supposed to. You need pins to ensure that the cylinder can’t turn with any old key. You need objects holding the shackle in place that can be removed once the plug is turned. You need a shackle that can release once the lock is unlocked.

So the next time you see a padlock, you now know the details of what’s going on on the inside of it. You know how these parts are made, how they connect to each other, and how they work. Even the best padlocks aren’t impenetrable, but they’re effective for any low-security applications.

Overall, padlocks are complex, and this complexity is necessary for ensuring that their ability to keep things secure stays a big part of their design. Padlocks are small but made of intricate pieces that all come together to form a functional whole.

Category: Lock Types, Tools of the Trade

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