How is it that one key, different from others, can open the same lock assigned to the different locks?
In: 7
It is not about the key. Nothing about the key is special.
It’s all about the lock. The lock’s “code” is determined by the length of the pins.
By putting multiple pins in the same hole, we can allow for two (or more) different key cuts to rotate the cylinder. A building with a master key has every lock set to use two different key cuts. One of those key cuts is the master key cut.
Nothing on one, slight click on 2, counter rotation on 3…..
Inside the lock are a bunch of pins in a row. Each row contains 2 pins, one on top of the other. The pins are different heights. When you insert a key the pins are lifted. This aligns the spot between the two pins with the outer edge of the cylinder, allowing it to rotate. If the arent at the right height at least one of the pins blocks the cylinder from turning.
For locks with a master key there are three pins in each row instead of two. One of the spots between the pins aligns for the master key, the other spot aligns for the lock’s individual key. It basically allows two different keys to work in the lock.
If you are having a hard time visualizing it from my description there are tons of pictures and short videos available with a quick hoogle search.
Most modern locks are pin tumbler locks. There is a row of pins that gets pushed up by the key. The right key will align the pins with the shear line so that the tumbler can rotate. But the most common master lock systems have wafers in the pin stack. So there are two different positions which will both align with the shear line. That means that two different keys can both unlock the lock.
There are several ways to have have a lock that can be opened by multiple keys. Probably the most common way is by master pinning.
Typical keys have 5-7 rows of pins the teeth of the key move up and down. Each key has their teeth set to different depths or ‘bitting’ Like 25143. In order for a lock to work on a key with the first row set to depth 2, it’d need a length 2 pin in it’s first row and 5143 in the following rows
So how do I set a lock to work on key 25143 and key 55143? By stacking a length 3 pin on top of it’s length 2 pin.
When a depth 2 key is inserted, the 3 length pin sits above the cylinder and the length 2 sits inside of it, allowing the cylinder to turn over.
When a depth 5 key is inserted, the length 3 pin sits ontop of the length 2 pin inside the cylinder, since when you combine the length of the 2 pin with the 3 pin it equals 5, it’s just like having a length 5 pin there. That’s how it works on both keys.
Their are other ways of making multiple keys work on a single lock, but they’re less common. I’ll cover them if asked.
When you insert a key into a lock it causes “pins” to move up and down as they rest on the jagged edge of the key.
Each of these pins is actually cut in 2 pieces. Each pin sits higher or lower depending on where on the key it rests. The cuts in the pins are designed such that all of the cut lines line up when the correct key is inserted into the lock. This is what allows the lock to “unlock” and the cylinder to turn.
Locks that have a master key option have pins that are cut into 3 sections rather than 2. One of the cut lines is for the normal key, the other cut line is used when the master key is inserted. Allowing 1 lock to unlock with 2 different keys.
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