How are keys made?

[marmaduke]

How is each key made to be individual and only work with one particular lock? How many combinations can there possibly be?

[netibiza]

It all to do with the rollers in the actual lock, which come down onto the ridges of the key, wrong key and the rollers won't fit properly - thats all I know

[brachiopod]

Have a look at this site first, to see how locks work;

http://home.howstuffworks.com/lock-picking4.htm

You will then see that there are a finite number of combinations that would be a function of the number of levers, the number of possible lever pin lengths and their relevant positions.

However, the number of combinations is still sufficiently large, so that the chances of inserting your key into a random lock (even if we all used the exact same make and model) and it opening it are very small..

Similarly, (and assuming a mass marketed product), it would be almost a certainty that there is a lock out there that your key would fit.

[BillyBB]

To meet BS3621 and have a kitemark there needs to be at least 1000 different keys to a range of locks. This is too many to feasibly try when you consider that there are many manufacturers with many types of lock all with a different set of at least 1000 keys.

A typical Yale cylinder rim lock could have 24000 different keys made before they repeat.

[BillyBB]

Forgot to mention, there are some manufacturers who guarantee not to repeat your key and others who make ranges in excess of 4000000000 different keys. You have to pay for this privilege though.