How to Bump a Lock: The Beginner's Guide
There are a lot of cool and unique ways to bypass locks, but among the most interesting is the craft of lock bumping.
By using nothing but a specially crafted key and a little impact force, you can quickly and easily open the majority of pin tumbler locks within seconds.
In this guide, we are going to cover everything that you need to know to bump a lock using a bump key.
We’ll begin by covering the bump key and the essential tools that you’ll need. Then we’ll learn how a lock works and what a bump key does to unlock it. Finally, we will learn how to bump a lock using the common pull-back method.
Let’s get to it!
Table of Contents
Tools Needed to Bump a Lock
Before we can learn how to bump a lock, we need to first discuss the tools required and ways to acquire them.
To bump a lock you need two tools—a bump key that fits your specific lock and some sort of bump hammer.
Let’s look at each tool and the options available.
The Bump Key
In a nutshell, a bump key is nothing more than a regular key in which the “cuts” are all made to the maximum depth possible.
The depths of the cuts are typically represented with a number between 0 and 9. A cut of 9 usually represents the deepest cut, while 0 is the shallowest.
The key below has been cut to a bitting of 99999—which is also why bump keys are sometimes called “999 keys.”
As you may notice, the teeth of the bump key are considerably short, however, they will still make contact with the pins when inserted into the keyway. We’ll learn the importance of this in a moment.
A bump key is defined by these maximum cuts and short teeth.
However, there is one additional thing that we need to consider—bump keys are not universal.
Bump keys, like all keys, only fit a particular keyway.
A bump key for a Schlage will not fit into a Kwikset lock and if you want to bump a Master Lock #3 you’ll need a bump key made for a Master Lock #3.
You can buy bump keys at just about any online lock picking shop, including our selection of bump keys here.
Additionally, you can also make your own by filing down the bitting of a regular key with a triangle file.
The Bump Hammer
Bump hammers are tiny mallets that are used to hit the head of the key and jolt it into the lock.
Just like bump keys, you can find bump hammers everywhere online. We also carry Peterson bump hammers here at Art of Lock Picking.
However, you don’t need a professional bump hammer to bump a lock. You can also get away with using other hard objects such as a rubber mallet, screwdriver handle, or block of wood.
As a last resort, you can also wrap your hand with some cloth and hit the key with your palm.
How a Pin Tumbler Lock Works
To fully understand how a bump key works, we first need to know how a pin tumbler lock operates.
In regards to lock bumping, there are 6 parts of a pin tumbler lock that you need to know.
- The Cylinder: The main body of the lock that contains the other functional parts of the lock.
- The Plug: Rotates within the cylinder and contains the keyway.
- The Shear Line: The physical gap between the cylinder and the plug (represented by the green dashed line).
- The Key Pins: The lower set of pins (red) that make contact with the key. Are a variety of heights to match the cuts of the correct key. This will become clearer in a moment.
- The Driver Pins: The upper set of pins (blue) that sit between the key pins and the springs. These pins restrict the plug from rotating by sitting in both the plug and cylinder and obstructing the shear line.
- The Springs: Push the driver pins back into the plug.
Check out the animation below to see how all these parts work together.
As the key is inserted into the lock, the key pins fall into the cuts.
If the correctly cut key is used, the height of the key pins and the bitting of the key will match perfectly and raise all of the driver pins to the same position.
Additionally, the gap between the key pin and the driver pin will match with the shear line—thus removing the obstructions from the shear line and allowing the plug to rotate freely.
Simply put, the goal of lock bumping is to remove the driver pins from the plug while keeping the key pins in the plug.
Knowing this, let's move on and finally learn how to bump a lock with a bump key!
How to Use a Bump Key
Alright, the time is here. Let’s finally learn how to bump a lock!
There are several common lock bumping techniques, but let's look at the most popular procedure called the "pull-bump method."
Step 1: Insert the bump key into the lock.
To begin, insert your bump key into the keyway and push it all the way in. Then slowly retract the key one cut, or until you hear at the rear pin drop.
At this stage, we are pulling the key slightly back so that we can later drive the teeth into key pins.
Step 2: Turn the key.
Apply a slight turning force to the key in the unlock direction—check out my article for guidance on which way your lock turns to unlock.
Also, be sure not to turn the key too hard.
At this stage, we are applying a turning force to the key in preparation for the driver pins to leave the plug. Once the driver pins are out of the plug, the key will continue to rotate and the lock will unlock.
Step 3: Strike the back of the key.
While maintaining a light turning force on the key, strike the head of the key with your bump hammer. Strike it straight on and rather hard.
When the key is hit, it will launch into the keyway and the teeth of the bump key will slam into the key pins, causing them to fly upward. With the help of Newton's third law of motion, the key pins will hit the driver pins and transfer their energy. In response, the driver pins will fly away from the key pins.
If done correctly, the driver pins will fully exit the plug and the key will turn fully, disengaging the lock.
You now know how to bump a lock!
That's all there is to it!
What If the Lock Doesn't Open?
If the lock doesn't open after the first hit, repeat the three steps above. Every few hits, release the turning force on the key to reset the pins.
While bumping try hitting the key with different intensities of striking force, as well as applying different degrees of turning force on the key.
An alternative technique that you can try is by applying the turning force directly after the bumping force.
So rather than applying the turning force prior to bumping, try quickly turning the key immediately after striking the key.
This technique requires a lot more finesse and skill, but it is a powerful technique that can even get you past security pins and other security features.
Frequently Asked Questions
How to Bump a Lock Without a Bump Key
If you don’t have a bump key you can also bump a lock using a lock picking technique called ranking. This can be accomplished using lock picks, or improvised tools such as bobby pins.
To learn more about lock picking and raking, check out my ultimate lock pick guide.
Do Bump Keys Actually Work?
Bump keys work very well and are highly effective against 90% of pin tumbler locks. Most locks can be bumped in under 30 seconds and leave no noticeable evidence that the lock was compromised.
Can You Bump a Deadbolt?
Deadbolts are just as susceptible to lock bumping as other types of locks. However, if you’re willing to upgrade your locks, there are deadbolts on the market that utilize bump-resistant technology.
Universal Bump Key
Bump keys are not universal and will only work for the specific keyway that they fit into. For example, master lock keys won’t fit into Kwikset keyways.
Bump keys are a blast to use and can provide any hobby lock picker with a new challenge and hours of fun.
However, like our old uncle Ben use to say, “with great power comes great responsibility.”
Always remember to live by the two golden rules of lock picking.
- Don’t pick a lock in use.
- Don’t pick a lock you don’t have permission from the owner to pick.
I hope this guide provided you with a good framework on how to use bump keys.
As always, happy picking!