Exterior Home Security

New Security Threat Unlocked: Everything to Know About Lock Crunching

There are several techniques burglars might use to bypass a lock, but few are as popular as lock crunching. But what is lock crunching, and is there anything you can do to prevent it?
A close up of a brass door knob attached to a red door.
Photo: istockphoto.com byllwill

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Q: Our neighbors’ home was recently burglarized, and they told us the thieves used a common technique known as “lock crunching.” My husband and I have never heard of the term; what is lock crunching, and how do you open a lock with this technique? Most importantly, what can we do to improve our front door security and stay safe?

A: Lock crunching is a scary break-in method that most people don’t even know exists. In short, lock crunching is a method used to crack through locks and gain access to a home via an exterior door. It’s shockingly easy to master, making it a go-to method for all types of burglars.

Fortunately, there are a variety of things you can do to reinforce your door or enhance the security of your property. The easiest way to prevent lock crunching is by installing a deadbolt, as these can’t be opened by lock crunching. Door jammers and home security systems can also be installed for added protection.

Take a closer look at lock crunching, including how it works, why criminals employ the technique, and what you can do to improve front door security and keep your home safe.

Lock crunching is a method originally used by locksmiths, but it has since been adopted by criminals as a way to break into a home.

Like most lock-picking techniques, lock crunching was first perfected by professional locksmiths before being co-opted by criminals. It joins a list of techniques, such as lock bumping (also known as door bumping) and lock snapping, that give burglars easy ways to bypass physical locks.

When someone is locked out of their home and needs to get inside fast, lock crunching is one option in a locksmith’s tool bag of tricks. If the person who is locked out has more time, the locksmith might be able to employ more delicate techniques—but if time is of the essence, lock crunching is a popular option among professionals.

Unfortunately, the popularity of lock crunching has also grown with burglars. Because it’s relatively easy to execute and works fast, many criminals use it to break inside a home with just a few minutes of effort.

A close up of a door handle in a brown door.
Photo: istockphoto.com: FabrikaCr

The technique uses common household tools along with force to crush the exterior of a lock.

Lock crunching is a forced-entry method that combines blunt force with standard household tools. When deployed in the right way, it’s possible to use the tools to remove the lock’s exterior and gain an inside look at the complex system of pins and levers hiding behind the metal chassis.

With a bit of practice, many thieves can have this process completed in just a matter of seconds. And because it doesn’t require specialized tools beyond what can be found in a typical household, anyone interested in lock crunching can purchase the gear needed to carry out the operation.

If lock crunching doesn’t work as intended, those same lock-crunching tools can sometimes be used in other lock-picking techniques, such as bumping the lock and lock snapping. In other words, most criminals will be able to acquire the tools to crunch locks, snap locks, or bump locks without much trouble, which makes it important for households to protect against as many techniques as possible.

An intruder can then access the interior of the lock mechanism, which can be quickly and easily picked to allow access to the home.

Once a lock has been “crunched” and its exterior frame is removed, a burglar can get to work on the lock mechanism inside. Picking a doorknob lock requires careful manipulation of a series of pins and levers, which is a process that’s typically very difficult.

Alternatively, burglars can use lock crunching to destroy the entire lock mechanism, leaving it in shambles and opening a lock without needing anything other than brute force. This is particularly concerning to most households, as it means anyone with the tools can break into a home without any special training.

Although it can be hard to identify a lock that has been tampered with, there are several telltale signs of lock crunching to keep an eye out for.

It can often be challenging to tell whether a lock has been targeted by a thief. For example, a lock that has been picked with standard methods often doesn’t have any signs of forced entry. However, that’s not exactly the case with lock crunching.

Most locks that have been the target of a lock-crunching attempt will have significant damage to their exterior frame. This can come in the form of major dents and dings around the metal chassis, or minor scratches if the thief stopped the attempt shortly after starting. It’s also possible for the entire exterior shell to be missing, with the internal mechanisms of the lock entirely visible.

Those who think their lock has been tampered with will want to look for telltale signs. This includes areas where paint has been scraped away to reveal the metal underneath, bent lock edges, deep scratches, and even damage to nearby objects like the door frame. When in doubt, the home’s residents can always reach out to a professional locksmith to examine the lock and see if it has been tampered with.

A close up of a person's hands testing a door lock with a key.
Photo: istockphoto.com: vovashevchuk

Classic cylinder locks are susceptible to lock crunching. Unfortunately, they are also the most common type of lock in the U.S.

Classic cylinder locks are one of the most popular types of door locks, thanks to their relative affordability and easy installation process. They’re also incredibly durable, allowing a home to go years without residents needing to worry about replacing its lock. If these locks do need to be replaced, the process is rather straightforward and doesn’t require a massive overhaul of the door. Cylinder locks can also be rekeyed when new residents move into a new home or for other security purposes.

Cylinder locks aren’t perfect, however, and one of their biggest drawbacks is how susceptible they are to lock crunching. Intruders who don’t succeed at a standard lock-picking attempt can quickly shift to lock crunching and find success with cylinder locks. This makes cylinder locks less than ideal if lock-crunching techniques have been reported in the neighborhood, as they have limited defense mechanisms against this particular break-in method.

To prevent lock crunching, install deadbolts and replace any exterior cylinder locks with electronic or smart locks.

Homeowners who have cylinder locks on their doors may want to consider installing secondary security gear to help protect their doors. The best options are often deadbolts, as these are incredibly difficult to break without using extreme force—so much force that intruders are bound to make a racket, thereby drawing attention to their actions.

Deadbolts serve as a second lock that will need to be bypassed before a home can be entered. This means intruders will need to crunch the cylinder lock, then find a way to remove the deadbolt. When a deadbolt and a cylinder lock are both used, this offers enhanced protection for most doors.

Alternatively, shoppers can look into replacing their existing cylinder locks with smart locks. These are less vulnerable to lock crunching, though they can be more expensive than traditional locks. They do, however, offer plenty of additional benefits, such as giving users the option to open the door lock without a key via a passcode or via a fingerprint scanner. Many can also be monitored remotely using a mobile app, giving customers added peace of mind that their door is closed and locked. Customers who need help finding the right product will want to start their search with the best door locks.

Consider other ways to secure a door, such as using a door jammer, a security bar, or a floor barricade.

Installing a new deadbolt lock or replacing a cylinder lock can be both time-consuming and expensive. Customers who are not interested in going to these lengths can instead opt for low-tech security measures such as a door jammer or security bar to prevent break-ins from lock crunching.

Door jammers and security bars come in a variety of styles. Many can be wedged below a door handle and propped up on the floor, giving the device extra strength and limiting lock-crunching attempts. Others are installed horizontally across the door frame, preventing the door from being kicked in from the outside. The best door security bars are durable and reliable, and because there are so many options, shoppers will want to consider all types before making a purchase.

Floor barricades are another option, as these serve as interior locks that securely fasten the bottom of a door to the floor. They’re essentially deadbolts, but instead of connecting a door to the door frame, they connect the door to the floor. Shoppers with serious safety concerns may want to consider pairing a floor barricade with both a door jammer and a smart lock.

If a door lock is broken, there are ways to temporarily lock a door without a lock. Security bars are a popular method, making them useful beyond stopping lock-crunching attempts. When employed properly, many of these products are also strong enough to secure a door from being kicked in.

Consider installing a home security system to deter intruders and keep your home more secure.

Adding hardware to doors such as deadbolts and door jammers is a great way to prevent break-ins, but nothing is entirely foolproof. In case an intruder does attempt lock crunching, having a security system installed can capture it on film for the authorities.

Better yet, many criminals are immediately deterred by the presence of a security system. Once they know they’re on film, they back off the property. This is a good reason for homes to have a comprehensive security system in place, including cameras, motion sensors, entry sensors, and floodlights. Placing security signs in the front yard and backyard can also deter criminals from approaching a property.

When deadbolts and door jammers are combined with one of the best security systems (such as one from Vivint or ADT), criminals are less likely to target a property. Lock crunching is primarily used to bypass cylinder locks, so homes with deadbolts, barricades, security cameras, motion detectors, and floodlights give burglars several obstacles that can’t be avoided.