Doors, Bolts & Lock Mechanisms: How They Impact Your Safe's Security

The door is the strongest part of a gun safe, but aside from the lock, a lot of people don't think about what goes into the door to make it so strong. In a good gun safe, every part of the door is specifically designed to give it the strength to stand up to an thief's attack. Below we'll explain four parts of the door that work together to give you the security you need to protect what's yours.

Along with these systems, another important part of the door is the lock's drill protection, but there's enough detail on that subject that we've wrote a separate article. Click here to learn more about locks.

Door Thickness

Let's start with the simplest and most basic concept, the thickness of the door. In a way, how thick the door is will determine the basic difficulty someone is going to have getting in. A 3/8" solid plate is going to be a whole lot harder to cut, drill and pry then a 16 gauge.

There are also different types of doors:

• Composite Door: A composite door (or rolled composite door) is a steel plate that's rolled inwards at the edges to meet an inner steel plate, usually with a sheet of fire board in between. It's designed to give you multiple layers of steel defense as well as add fire defense to your safe. The inner plate varies in thickness and length, and at minimum covers the lock area and at maximum covers the entire length of the door to protect the door's whole locking mechanism. The thicker the steel in the door, the stronger it will protect against force, heat and pry attacks.

Here's what a rolled composite door looks like.

• Steel Plate Door: A steel plate door has a single, thick steel plate instead of the outer and inner plate. The steel is usually thicker then either one of the composite door plates, but the trade off is there's only one plate. However, the extra thickness is great for defending against power tools and pry attacks. If there is any fire protection, it's somewhere in the inner door housing.

• Hybrid Composite/Plate Door: Some safes have some cross over of the two designs. It might be a rolled composite door, but with another steel plate wielded to the front of it. It might be a steel plate with a 2-step design that makes it extraordinarily hard to pry, drill or cut.

Locking Mechanisms

Locking mechanism refers to the system of gears, plates and other components inside the safe that move when you turn the handle to open or close it. This is also called the "bolt work". Its purpose is to extend and retract the bolts that keep the safe from swinging out, and the entire mechanism is made immobile when the bolt of the safe lock comes down. While the designs range from very simple to very complex, the concept is always the same.

Here's the general concept of a locking mechanism.

So, why are there so many differences in designs? While even a simple design can do wonders, the components can be basic, and with some knowledge and ingenuity a thief might think of a way to defeat it. Manufacturers add extra and more complex features to reinforce the mechanism. For example, adding extra actuator plates can reinforce the bolt bar and make it more rigid. Liberty Safe adds an over-center cam to keep people from trying to pound the outside bolts, attempting to dislodge the lock. There are a lot of different locking mechanisms, and they all bring something to the table when it comes to defending against thieves.

Bolt Design

When a safe is locked, it's the bolts that extend out behind the door frame and keep the door from swinging open. That's really the core concept. If someone can figure out how to get the bolts to retract, get the bolts to bend or get a safe's door frame to bend, they can get the bolts to where they're no longer holding the door closed. So, the bolt design needs these three features to keep that from happening.

• Surface Area: On a good safe, the bolt system extends almost the entire length of the door, so a thief can't just pry in one spot and get the door open. So, the thicker the bolts and the more there are, the more he has to work to get the entire door open. And that's not just the sides. If the safe has bolts on the top and bottom, it will really make it a whole lot harder on him.

• Depth or Length: Another feature is the depth (or length) of the bolt. If the bolt is short and stubby, it will be easier to pry it from the inside of the door to the outside. The deeper the bolt goes behind the door, the harder it's going to be to get it to flex or bend enough to get it to the outside.

• Rigidity: If you look at the round bolt design, you'll see that the bolts are attached in some way to a long angle iron (it's actually steel). While it's not easy to do, it can flex with enough torque. A lot of manufacturers find ways to reinforce this angle iron to keept it rigid.

Liberty Safe's Military Locking Bolt Design.

Superior Safe's Classic Round Bolt Design.

Slip Clutch

If you can't outsmart it, break it. That's what a lot of thieves try to do when it comes to the safe's handle. The idea is, if you apply enough force to the handle shaft, you might break some part of the mechanism inside, and then you'll be able to retract the bolts. The answer to this is the slip clutch. If someone applies too much pressure, the handle will simply slip a bit. You can turn the handle just fine when you unlock the safe, but if the safe is still locked, the handle will just keep slipping, making sure no one breaks the mechanism and forces open the safe.

A safe is simple in concept, but really it has a lot of systems in place to keep thieves out, and these systems can go from very basic to extremely complex. When we say the door is the strongest part of a safe, it's because the systems in place can make it extremely difficult for a thief to defeat. Learning what goes into a door's security can help you make an informed decision on the safe you want protecting your valuables.