Pin and tumbler locks are the ones that you’re most likely to find on doors in the U.S. In fact, 90% of all U.S homes are protected by pin and tumbler locks. The original design of this lock consisted of a series of single pins. When these were locked, they kept the bolt from moving by being pushed into the bolt itself. The key was used to lift the pins out of the bot, allowing the bolt to move freely. This was the first instance of a shear line, folks! This major discovery paved the way for modern locks. Early locks we’re made out of wood, but metal soon became the material of choice. Brass locks followed, and then the use of iron. The Yale Company modified the pin and tumbler lock, making it smaller and better at its job. The lock hasn’t changed much in its core design since then, but different add-on’s to the method have been applied in modern locks. Features like sidebars, ball bearings, hardened steel and security pins are auxiliary components that enhance modern lock security.
Pin tumblers are tacks in a lock that are pushed down by a spring. In order to separate the pins from the shear line, each pin must be raised to a specific level. Once the pins are freed from the tumbler, the lock is open and can be manipulated freely. From there you can lock or unlock the bolt inside. The edge of the blade in traditional pin and tumbler locks are the bitting area. There have been a few small changes to the internal components of pin and tumbler locks over time, but the base design and function remains intact. Newer designs like axial//tubular locks and dimple locks offer better security than their traditional counterparts. A key that is not designed to match the biting in a pin and tumbler lock will not be able to move the bolt.
Components Of A Tumbler Lock
- Key pins (bottom pins) – The key touches theses pins when it is first entered. Key pins come in different sizes and shapes in order to match various key cuts. Driver pins (top pins) – These pins are placed in between the springs and key pins. They block the rotation of the plug in the lock position. Driver pins can be cut in different shapes to deter illegal picking.
- Plug – The plug is the part of the lock that you rotate with the key when you insert it into the lock. The plug won’t move if the key is incorrect, and it is connected to the cam of the lock.
- Cylinder – The lock cylinder is the outer part of the lock that contains the upper pins and plug. The driver pins and spring regress into the cylinder’s cavity when the lock is properly opened.
- Cam – The cam of a lock is an extension of the plug. The cam is an extension connected to the back of the plug which actuates the bolt mechanism to lock or unlock the lock.
Springs – The springs placed above the pin stacks push the pins down to their resting position to make sure they can’t be trapped above the shear line while the plug is in the default position.
Pin tumblers are easy to tamper with. There are many ways to compromise these locks such as bump keys, pick guns, impressionism, comb picks, decoding, and destructive and bypass entry. Pin and tumbler locks can be fortified with other lock mechanisms for enhanced security.
Dimple locks are pin and tumbler locks named as they are because of the fashion of their bitting. These grooves look like dimples. These locks are a bit more complex than the classic pin and tumbler locks. The plug rotates when the dimples are aligned properly with the shear line in the lock. The orientation of this lock differs from the classic design, making it seem a bit more sophisticated. On these locks, the flat side of the key has the biting instead of the front. With dimple locks the key can be inserted in any direction. The key also doesn’t go as deep into the lock as with regular pin and tumblers. The amount of pin positions possible with dimple locks grants more key control, giving the lock more master key abilities.
You can find dimple locks on both the low and high end of security. More advanced dimple lock systems feature amendments like side pins, axial rotation, telescoping pins and key profiling. Pick guns don’t work very well against dimple locks because they lack the range of motion that dimple locks are capable of. This kind of lock is still vulnerable to lock picking, comb picking, key bumping, impression, decoding and bypassing. There is a way to improve the security of these locks by combining them with other lock systems.
Tubular pin tumbler locks, also known as Ace locks, circle pin locks and radial locks, is a pin and tumbler lock with circularly arranged pins. The key that goes with these locks are cylindrical in shape. These types of locks are used on elevators, computers, bicycles, coin-operated laundry machines and vending machines. These lockers are generally more pick-proof than standard pin and tumbler locks. These locks can be picked with special tools or drilled into though. The addition of a middle pin in the keyway can prevent drilling, however.
There are various ways that a pin and tumbler lock can be compromised. It depends a lot on the type and construction of the lock in question. Talk with your local locksmith about which lock is best for you, especially about fortifying pin and tumbler locks against picking. These locks are notorious for being easily compromised, especially in the case of forced entry. Remember that locks are only one part of the security equation. Be sure to pay attention to the condition of your door, door jamb, strike plate and door frame. All of these factors contribute to better security for your home.