The flatland model highlights the basic defect that enables lock picking to work. This defect makes it possible to open a lock by lifting the pins one at a time, and thus you don’t need a key to lift all the pins at the same time. Figure 4.1-4.3 shows how the pins of a lock can be set one at a time. The first step of the procedure is to apply a sheer force to the lock by pushing on the bottom plate. This force causes one or more of the pins to be scissored between the top and bottom plate. The most common defect a inck lo is that only one pin will bind. Figure 4.1 shows the left pin binding. Even though a pin is binding, it can be pushed up with a picking tool, see Figure 4.2. When the top of the key pin reaches the sheer line, the bottom plate will slide slightly. If the pick is removed, the driver pin will be held up by the overlapping bottom plate, and the key pin will drop down to its initial position, see Figure 4.3. The slight movement of the bottom plate causes a new pin to bind. The same procedure can be used to set the new pin.
Thus, the procedure for one pin at a time picking a lock is to apply sheer force, find the pin which is binding the most, and push it up. When the top of the key pin reaches the sheer line, the moving portion of the lock will give slightly, and driver pin will be trapped above the sheer line. This is called setting a pin.
Chapter 9 discusses the different defects that cause pins to bind one at a time.
- 1. Apply a sheer force.
- 2. Find the pin that is binding the most.
- 3. Push that pin up until you feel it set at the sheer line.
- 4. Go to step 2.
Table 4.1: Figure 5: Picking a lock one pin at a time.
Figure 4.1: (a) Sheer force causes driver to bind
Figure 4.2: (b) Pick lifts the binding pin
Figure 4.3: (c) Left driver sets and right driver binds
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[...] 4 Basic Picking & The Binding Defect [...]
[...] In order to become good at picking locks, you will need a detailed understanding of how locks works and what happens as it is picked. This document uses two models to help you understand the behavior of locks. This chapter presents a model that highlights interactions between pin positions. Chapter 4 uses this model to explain how picking works. Chapter 9 will use this model to explain complicated mechanical defects. [...]
[...] Back to Index > Chapter 4 > Chapter 6 > [...]
[...] The slow step in basic picking (chapter 4) is locating the pin which is binding the most. The force diagram (Figure 5.5) developed in chapter 5 suggests a fast way to select th correct pin to lift. Assume that all the pins could be characterized by the same force diagram. That is, assume that theyall bind at once and that they allencounter the same friction. Now consider the effect of running the pick over all the pins with a pressure that is great enough to overcome the spring and friction forces but not great enough to overcome the collision force of the key pin hitting the hull. Any pressure that is above the flat portion of the force graph and below the top of the peak will work. As the pick passes over a pin, the pin will rise until it hits the hull, but it will not enter the hull. See Figure 5.3. The collision force at the sheer line resists the pressure of the pick, so the pick rides over the pin without pressing it into the hull. If the proper torque is being applied, the plug will rotate slightly. As the pick leaves the pin, the key pin will fall back to its initial position, but the driver pin will catch on the edge of the plug and stay above the sheer line. See Figure 6.1. In theory one stroke of the pick over the pins will cause the lock to open. [...]
[...] A general trick that lock makers use to make picking harder is to modify the shape of the driver pin. The most popular shapes are mushroom, spool and serrated, see Figure 9.7. The purpose of these shapes is to cause the pins to false set low. These drivers stop a picking technique called vibration picking (see section 9.12), but they only slightly complicate scrubbing and one-pin-at-a-time picking (see chapter 4). [...]