At its essence, a lock is puzzle. While its answer may vary slightly, the route to puzzle-solving success has remained largely unchanged since the pin-tumbler lock’s invention 4000 years ago in ancient Egypt. Manipulate the pieces in just the right way and the lock will yield.

At its essence, a lock is puzzle. While its answer may vary slightly, the route to puzzle-solving success has remained largely unchanged since the pin-tumbler lock's invention 4000 years ago in ancient Egypt. Manipulate the pieces in just the right way and the lock will yield.

Sure, a key is the easiest way in, but it's not the only one. Eric Michaud, the co-founder of Toool.us, the US chapter of the Open Organization of Lockpickers, which promotes greater public understanding how locks work and when they might not, walked us through the art of solving the lock's puzzle without a key.

What You Need

Lock: Any cheap, key-operated lock from the hardware store will do.

Tools: The basic path to success requires two instruments: a pick and a torque tool. Your basic pick will be a thin, pencil-length piece of metal that curves slightly upward at the end. The torque tool will be a flat piece of metal with the small end bent 90 degrees.

Understand the Puzzle

Before you can pick your way to the answer, you need to understand the puzzle and its pieces.

The two largest parts of a pin-tumbler lock are the body and the plug. They're also the elements of the lock that you can see. The body is the container, and the plug, which spans the length of the lock, is the cylindrical part that rotates when you turn the key.

If a lock were nothing but a body and a plug, any old key would open the lock. But that wouldn't make for a very secure system, would it? So lock makers decided to throw a perpendicular wrench in that turning mechanism by exploiting the intersection between the plug and the lock's body.

The metaphorical wrench is actually a line of stacked pins, each broken at different positions. When the correct key is inserted into the keyway, its grooves and peaks will push up the pins into a pattern that will allow the plug to rotate freely.

Image credit: Wikimedia Commons

To understand how the pins work, imagine two erasers, like the ones on the end of a pencil, stacked on top of each other. One eraser hangs into the keyway like an icicle, its top flush with the plug's outside edge. The other is stacked on top of the first, reaching up into the lock's body. Where they touch is also where the plug and the lock's body meet. If the erasers are aligned so they meet just at the shear line, the plug will rotate freely. But push the pair too far down into the lock, and the top eraser will straddle the two main structures, blocking the plug from turning and the lock from opening.

Why You Can Pick a Lock

Lining the pins up in a perfect row, as it turns out, is a bit of a manufacturing challenge. "The problem is that the drill bit will wobble so you get aberrations," explains Michaud. "You'd think that when you apply pressure, all the pins would hit at the same time, but they don't." Only one or maybe two pins at a time will take the brunt of the pressure.

If you don't know how many pieces are in the puzzle, it's hard to solve it effectively. To count the number of pins, insert the long end of the torque tool all the way into the lock and push up. As you slide the torque tool toward you slowly, the pins will spring free with a click. Count the clicks and you'll know how many pins you need to manipulate to open the lock.

Step 1: Get a Grip

Hold up your left hand like you're about to high-five someone. (Switch that if you're a lefty). Nestle the lock upside down between your thumb and forefinger so the key hole is facing you and the lock's bottom is flush with the back of your hand. Now rotate your hand down, fingers pointing toward you instead of toward the sky. The keyway should flip 180 degrees.

Step 2: Give It Torque

Insert the short end of the torque tool into the keyway and get it situated as low as possible. (You want to give yourself space to use the pick). The long end of the torque tool should extend toward your pointer finger. Rest your index finger on the long end of the tool, applying a slight amount of constant pressure. Michaud recommends just a few ounces, like that of a key-stroke. "If your finger is changing color, you're pressing too hard," says Michaud.

(Note on ergonomics: Locks can get heavy. Rookies will rest the weight of the lock on their wrists, but pros will advise otherwise. Either place your hand on your lap or on the cushion of the pinky side of your hand to ease the stress on your tendons.)

Step 3: Tease the Pins

Wiggling a paper clip around may work on the television, but be warned: it's a small screen lie.

Instead, hold the pick like you'd hold a chopstick or pencil with the curved end swooping upwards. Insert the curved end as low inside the lock as possible. Remember how many pins you counted inside the lock? Well you can't see them lined up in there, but you're going to start testing them. Pin by pin, work your way down the line, cupping each pin with the tip of the pick and lifting gently. You don't need to slam it to the ceiling; you just need to raise the stack to break at the sheer line.

If a pin is springy, skip it. The lock-picker's target is the binding pin. You'll know you're prodding the right one when the pin gives back a little resistance when you try to lift it.

That tension means that your torque tool, which is trying to spin the plug, is pressing the pin against the side of the lock. Lift the bottom pin up just enough and its accompanying top pin, called a driver pin, will break ever so slightly over the sheer line.

The lock will celebrate your small victory by shifting ever so slightly toward your torque tool.

Continue to move back and forth down the line, testing the pins for stiffness and spring. When each stiff pin's accompanying driver pin has cleared the sheer line—voila!—the lock should pop open.

Tools down! Now use that hand positioned for high-fives to actually give one.