The $501 Lock
Brooke Castro & Amelia Pludow

*It cost $1 for the materials to make our lock and $500

to replace the lock broken while learning how to pick locks

A traditional lock, like the kind on most doors, has a fairly simple design. The lock is made up of a cylinder, or plug, within an outer housing. There are pairs of pins that hold the cylinder and housing together. When the correct key is inserted, the pins are raised so that the break between the pins lines up with the break between the cylinder and housing, or the shear line. This allows the inner cylinder to be turned, which allows the latch to open.

This model lock shows what happens when a key is inserted into a lock.

Now try your hand at picking the lock:

1. Apply gentle force on the handle in the direction it should turn (pins towards you)

2. Try lifting each pin with the pick until one is held up

The lock should turn a little more creating a ledge to hold the pin up

3. Repeat until all the pins are lifted

4. Open the lock

This lock system has been used for thousands of years. Inclined planes on the key raise and lower each pin as the key moves into the lock, until they stop at their final height. These inclined planes provide mechanical advantage (MA) as shown:

MA = S/H

It is the imperfections in locks that allow them to be picked. The pins do not line up perfectly, so one pin holds the lock closed more than the others. It is this pin that can be picked first. Once it is held up, another pin has more force on it, which can then be picked.