Are Combination Locks Safe?
As opposed to the old fashioned kind that used to grace the handle of your dad’s junior high gym locker or secure a bike to the bike rack at school, today’s well designed combination locks come in many different shapes, sizes, colors and strengths. By definition, a combination lock will open only when the dial is turned through a specific, predetermined sequence of numbers and positions. When correctly entered or dialed in, this sequence lines up the internal structures of the lock, usually a series of disks, and allows it to spring open. It is a keyless lock.
Combination locks generally consist of a circular body that has a numbered dial on the face, with an inverted U-shape locking mechanism that is made of solid metal, usually stainless steel. When the lock is deactivated, this piece swings open so the lock can be slipped through or around whatever is to be secured, then clicked into place. Combination locks can also be permanently attached, such as to the lid of a briefcase, where a series of numbers (usually three or four) are clicked into place on a tumbler in order to lock and unlock the unit. Yet another type of combination lock involves a numbered or lettered electronic plate, where the proper sequence of numbers are pressed to gain entry.
Here is the typical method of disengaging a dialed combination lock:
1) Turn the dial to the right three turns and stop at the first combination number
2) Turn it to the left, pass the second combination number once, then stop on it the second time around
3) Turn the dial again to the right and stop on the third combination number
Since the likelihood of anyone guessing the exact numbers is pretty slim, combination locks tend to offer a high level of security. A lock with four internal disks has over 100,000,000 possible combinations! And while, in the old days (think about movies and TV shows from the 70’s, for example) a crook could put their ear to the lock or use a stethoscope and hear the tumblers clicking into place, modern combination locks are smooth and sophisticated in their movement, making it virtually impossible to open the lock without the combination. Bolt cutters can snip off a hanging combination lock (with a good deal of effort), but this type of forced entry is pretty obvious. So unless the combination gets out or the perpetrator is a math whiz, combination locks are pretty safe. Most modern combination locks can be reset.