Using a Lock Pick
It’s Easy
The main secret to opening locks with a lock pick is that it’s easy. Anyone can learn to pick locks. The theory behind lock picking is the theory of properly exploiting mechanical flaws. There are a few basic concepts and definitions, but most of the material consists of techniques for opening locks with certain defects or characteristics. The structure of this guide reflects that approach.
The first few chapters provide vocabulary and basic information about locks and lock picking. You can’t learn to pick locks without practice, so one chapter offers a set of carefully selected exercises to help you develop your lock picking skills. At the end, there’s a catalog of mechanical features and defects found in locks, and methods for identifying and exploiting them. The first appendix describes how to make your own lock picking tools. The next appendix covers some legal aspects of lock picking.
Don’t underestimate the exercises. The only way to learn to identify and use defects in a lock is through practice. You need to practice both on the same lock many times and on many different locks. Anyone can learn to open desk and file cabinet locks, but to be able to pick most common locks in under thirty seconds, you need practice.
Before we get into the details of locks and lock picking methods, it’s important to note that picking a lock is just one way to “bypass” a lock, and it causes less damage than methods based on brute force. In fact, it may be easier to bypass the locking mechanism than the lock itself. Sometimes it’s easier to bypass another part of the door, or even leave the door alone entirely. Remember: there’s always another way, and usually a better one.
How a Key Opens a Lock
Fig. 1.1 — Structure of a Pin Tumbler Lock
This chapter covers the basic features of pin tumbler locks and the vocabulary used in this guide. The terms used to describe locks and their parts vary from manufacturer to manufacturer and from city to city, so even if you’re already familiar with the basics, take a look at Fig. 1.1 for the terminology.
Understanding how a lock works when opened with a key is only part of what you need to know. You also need to know what happens during picking.
The sections “Horizontal Model” and “Vertical Model” describe models that help you understand how locks respond to picking.
Fig. 1.1 shows the vocabulary for real locks. The key is inserted into the keyway, which is inside the plug. The keyway has wards, which limit the number of keys that can be inserted. The plug can rotate when the correct key is inserted. The non-rotating part of the lock is called the hull (or shell). The first pin the key touches is called pin #1. The rest are numbered in order toward the back of the lock.
The correct key lifts each pin pair so that the gap between the key pin and the driver pin aligns with the shear line. When all pins are in this position, the plug can rotate and the lock opens. If the wrong key is inserted, some pins will block the plug from turning.
The Horizontal Model
Fig. 1.2 — Horizontal Model of a Lock
To learn to pick locks properly, you need to study in detail how locks work and what happens during picking. This guide uses two models to help explain lock mechanisms. This chapter describes a model that shows the relationships between pin positions. This model is used in the “Main Pin Defect” section to explain picking principles, and again in “Recognizing and Using Lock Features” to explain complex mechanical defects.
Fig. 1.3 — The Key Lifts the Pins
The “horizontal” model is shown in Fig. 1.2. This is not a cross-section of a real lock, but a simplified diagram. The purpose of this lock is to keep two metal plates from moving until the right key is inserted. The lock is made by placing two plates on top of each other and drilling holes through both. The diagram shows a lock with two holes. Each hole contains two pins, so that the gap between the pins does not align with the gap between the plates. The lower pin is called the key pin, as it touches the key. The upper pin is called the driver pin. Sometimes they’re just called driver and pin. A protrusion on the bottom of the lower plate keeps the pins from falling out, and a spring above the upper plate pushes down on the driver pin.
Fig. 1.4 — The Right Key Moves the Plates
When no key is inserted, the plates can’t move because the driver pins pass through both plates. The correct key lifts the pin pairs so the gap between the pins aligns with the gap between the plates (see Fig. 1.3). The key lifts the key pin so its top reaches the shear line. In this position, the plates can move.
Fig. 1.4 also illustrates an important feature of real locks: there must be a gap between any parts that move relative to each other. The gap between the upper and lower plates allows the lock to be opened by several different keys. Notice that the right key pin in Fig. 1.4 isn’t lifted as high as the left, but the lock still opens.
The Main Pin Defect
The horizontal model illustrates the main defect in pickable locks. This defect allows you to open a lock by lifting one pin at a time, so you don’t need a key to lift all the pins at once.
Fig. 1.5 — Left Driver Pin is Set, Right is Touching the Hole Wall
Fig. 1.6 — The Pick Lifts the Pin Touching the Hole Wall
Fig. 1.7 — Pin Touches the Hole Wall
Figs. 1.5 and 1.7 show how you can set the pins one at a time. The first step is to apply mechanical force along the lower plate. This causes one or more pins to press tightly against the walls of the holes in the upper and lower plates. The most common defect is that only one pin is pressed tightly against the hole wall. In Fig. 1.5, the left pin is tight. You can push it up with a pick (Fig. 1.6). When the top of the key pin reaches the shear line, the lower plate shifts slightly. When you stop pushing with the pick, the driver pin is held above the lower plate, and the key pin returns to its original position (Fig. 1.7). As a result of the slight shift, a new pin is now tight against the hole wall. You repeat the process for this new pin.
So, the method of picking a lock one pin at a time is to apply mechanical force along the lower plate, find the pin that’s tightest against the hole wall, and push it up. When the top of the key pin reaches the shear line, the moving part of the lock shifts slightly, and the driver pin is held above the shear line. This process is called setting a pin.
The section “Recognizing and Using Lock Features” discusses various defects that cause only one pin to be tight at a time.
- Apply mechanical force.
- Find the pin that’s tightest against the hole wall.
- Push this pin up until it sets above the shear line.
- Repeat from step 2.
The Vertical Model
The horizontal model can explain effects involving more than one pin, but to explain the behavior of a single pin in detail, we need another model. The vertical model shows the relationship between the torque applied to the plug and the force needed to lift each pin. Understanding this relationship is crucial.
To “feel” what’s happening during picking, you need to know how the torque applied to the plug and the pressure from the pick affect pin movement. This is best shown with a graph of the minimum pressure needed to lift a pin versus how far the pin is moved from its original position. At the end of this chapter, a force graph based on the vertical model is provided.
Fig. 1.9 shows the position of a pin after torque is applied to the plug. The driver pin experiences friction on both sides, spring force from above, and contact force from the key pin below. The amount of force you apply with the pick determines the contact force from below.
The spring resistance increases as the pins are pushed up, but this increase is minor, so we’ll assume the spring force is constant for the pin movements we consider. Pins will only move when you apply enough force to overcome the spring. The friction force is proportional to how tightly the driver pin is pressed against the hole walls, which in turn is proportional to the torque. The more torque you apply, the harder it is to move the pins. To move a pin, you need to apply more pressure than the sum of the spring and friction forces.
Fig. 1.8 — Vertical Model
Fig. 1.9 — Pin Touches the Hole Wall
Fig. 1.10 — Pins at the Shear Line
Fig. 1.11 — Key Pin Enters the Hull
As the pins are pushed into the hull, the key pin starts to experience friction similar to what the driver pin had in its original position (Fig. 1.11). So, about the same pressure is needed to move the pins up to and past the shear line. As torque increases, so does the required pressure. At the shear line, the pressure increases sharply, as the key pin hits the hull. All these forces are shown graphically in Fig. 1.11.
Fig. 1.12 — Pressure Needed to Move Pins
Basic Principles of Raking
Fig. 1.13 — Driver Pin Catches on the Plug
When practicing lock picking at home, there’s no need to rush, but in real situations, speed is crucial. This chapter describes a method called “raking,” which allows you to quickly open most locks.
The longest step in picking is usually finding the pin that’s tightest against the hole wall. The force diagram (Fig. 1.11) above suggests a quick way to find the right pin to lift. Suppose all pins can be described by the same force diagram, meaning they all press tightly against the hole walls and experience the same friction. Now, if you use the pick to apply enough force to all pins to overcome the spring and friction, but not enough to push the key pin into the hull, you’ll be in the right range. Any pressure above the horizontal line and below its peak on the force graph will work. When the pick passes over a pin, it lifts it to the hull, but doesn’t push it in (Fig. 1.9). The pick’s pressure is countered by the collision force at the shear line, so the pick doesn’t push the pin into the hull. With the right amount of torque, the plug shifts slightly. When the pick stops pressing, the key pin returns to its original position, and the driver pin is held above the shear line by the plug (Fig. 1.13). In theory, one pass of the pick is enough to open the lock.
In practice, one pass usually sets only one or two pins, so you need several passes. You “rake” the pins back and forth with the pick while applying torque. Exercises will teach you how to choose the right torque and pressure.
You may find that the pins tend to set in a certain order. This order is determined by many factors (see “Recognizing and Using Lock Features”), but the main reason is a misalignment between the plug’s center axis and the axis of the pin holes (Fig. 1.14). If the pin holes are offset from the plug’s center, the pins will set one by one as the plug turns in one direction, and also one by one in the opposite direction if turned the other way. This defect is common in many locks.
Fig. 1.14 — Pin Hole Placement in the Plug
Raking is a fast method because you don’t have to spend time on each pin individually. You just need to find the right torque and pick pressure. Fig. 1.13 shows all the steps of raking. Exercises will teach you how to tell when you’ve set a pin and how to apply the right forces. If the lock doesn’t open quickly, it probably has one of the features described in “Recognizing and Using Lock Features,” and you’ll need to pay special attention to individual pins.
- Insert the pick and tension wrench. Without applying torque, remove the pick to feel the spring stiffness.
- Apply slight torque to the plug. Insert the pick without touching the pins. As you remove the pick, press on the pins. The pressure should be just above the minimum needed to overcome the springs.
- With each pass, gradually increase torque until the pins start to set.
- While keeping torque steady, rake back and forth over the pins that haven’t set. If some pins still won’t set, reduce torque and start again with the previous torque level.
- Once most pins are set, apply more torque and rake with slightly more pressure. This will set pins that weren’t lifted high enough, for example, due to beveled edges.
Components of Lock Picking Skill
Anyone can learn to pick simple locks. Picking complex locks, however, is a craft that requires mechanical sensitivity, physical dexterity, visual focus, and analytical thinking. There are many ways to improve if you want to master lock picking.
Mechanical Skills
Learning to rake pins with a pick is surprisingly difficult. The problem is that most mechanical skills you’ve learned before involve using a fixed hand position or path, regardless of the force needed. In lock picking, you need to apply a fixed force regardless of your hand’s position. When removing the pick from the lock, you need to apply consistent pressure to the pins. The pick should “bounce” up and down in the keyway depending on the resistance from each pin.
To pick a lock, you need to be aware of your hand movements. To develop this awareness, practice listening and feeling as the pick passes over the pins. This mechanical skill can only be learned through practice. Exercises will help you recognize important feedback from your fingers.
Imagination
To master lock picking, you need to develop visual-reconstructive imagination. This means using information from all your senses to picture what’s happening inside the lock as you pick it. You need to “project” all your senses onto the lock to get a complete picture of how it responds to your actions. Once you can visualize this, it becomes easy to choose the right actions for picking.
Information about the lock comes through all your senses. Most comes through touch and hearing, but other senses are important too. For example, smell can tell you if the lock was recently lubricated. As a beginner, you’ll need to use sight to coordinate your hands, but as you improve, you’ll find you don’t need to look at the lock. In fact, it’s often better to rely on information from your fingers and ears rather than your eyes.
The key to this skill is calmly focusing on the lock. To achieve this, try to simply let go of all thoughts and feelings unrelated to the lock, rather than straining to concentrate.
Analytical Thinking
Every lock has unique features that make it harder or easier to pick. If you learn to recognize and use these “personal” features, you’ll learn to pick locks faster. Mainly, you need to analyze the feedback you get from the lock to identify its features, and then, using experience, choose the right picking method. The section “Recognizing and Using Lock Features” covers many common features and ways to use or overcome them.
People often underestimate the analytical skills used in lock picking. They think the pick opens the lock, and the tension wrench is just a passive tool that applies pressure. Let me suggest another view: the pick just runs over the pins to gather information about the lock. Based on your analysis of this information, you apply the right torque with the wrench to set the pins and align them at the shear line. It’s the tension wrench that actually opens the lock.
Changing the amount of torque you apply as the pick moves in the keyway is a common way to solve several problems. For example, if the middle pins are set but the end pins aren’t, you can increase torque as the pick passes over the middle pins. This reduces the chance of disturbing already set pins. If a pin doesn’t seem to lift high enough, try reducing torque on the next pass.
The skill of applying the right torque while working the pick requires careful hand coordination, but as your ability to visualize what’s happening inside the lock improves, so will this important skill.
TO BE CONTINUED