Recently moved to a gym that uses padlocks for locking your stuff, they sell them too for an inflated price of 3.5$, jokingly I tried my key on a friend’s lock, and one more random one, of course it didn’t work and it made me curious.
My question is how do factories make all keys/locks different even at these cheap mass produced kinds that are probably sold for 0.5-2$, how is it worth for a factory to “use different patterns” at that price, or how do they do it?
In: Engineering
Locks have pins inside of different lengths and they have to line up at the same spot to turn the lock. You just set a machine to put in the ones of the same length to match a key.
Some locks have the code printed on the keys. 17432 for example are the pin lengths. Size 1 then 7 then 4 then 3 then 2.
Some locks use a coded algorithm and might have 2314 on them which actually decodes to 17432 for pin lengths.
Look up Lock Picking Lawyer or Deviant Ollam on YouTube for more info.
Some key/lock manufacturers guarantee that your lock is the only individual that uses that exact key.
Others guarantee that you are alone with it in your country.
Some keys are so easy to copy that it makes no difference that the keys are unique.
With cheap pad-locks, there is usually a rotation of a given number or combinations that recur at regular intervals. Every 1000 locks. Every 10 000 locks. Or in a bad scenario, every 20 locks.
If you want all of the keys, you can literally purchase a shipping pallet with those locks in retail packaging and extract all the keys.
This is unfortunately also true for car doors. Car manufacturers also use rotations of keys with a given number of combinations. Not necessarily that high a number. (nowadays, thankfully, the car requires a *immobiliser chip* in the key that communicates the keys electronic identity to the car when you turn the ignition; it’s enough to get into the car, but not enough to drive off with it.)
The answer to your question is more or less that it’s worth to have different patterns because it’s a cost of doing business. If you buy five padlocks, no matter how cheap, you expect them to have five different keys. Else you feel cheated on and want to return them all. They HAVE TO have rotation, the question is just how many unique combinations they are rotating.
They aren’t at all. I’ll bet if you went to Home Depot and bought 10-15 of the same master lock with a key that two will be the same. lol master lock is well known for mass production.
The basic locks are mass produced, but the actual security code is individualised. There are different pins that recognise different depth cuts on the keys.
So, a lock body gets to the pin insertion stage of production. It gets pin type 1 in slot 1, pin type 3 in slot 2,pin type 4 in slot 3. Then the lock is labelled with the pin codes. The lock is sealed up. Then it goes to the key stage, the pin code is read off and a key cut to the correct shape. The keys and lock are packaged up together.
The next lock down the production line gets a different code like 225. When it gets to the key station, a key is cut to match.
On low grade locks, there might only be a few hundred or thousand different key codes. This means that you will get several locks with the same keys by chance.
High quality High security locks can have quadrillions of possible key shapes. Each lock gets a randomised code which is checked against of every lock of that type ever made, so that 2 locks never share the same key, unless the customer specifically requests it.
If you have 5 different positions to consider on a key, each of which can have 6 different meaningful lengths, that producess 15625 possible combinations. That’s not many, and that’s for a key that’s supposedly fairly secure and widely used for house security.
For a house you can improve that security by having two locks on each entry way, which would mean that you’d have over 100 000 000 combinations, even if they’re from the same manufacturer/same standard. That’s much better.
For gym lockers and the like (and bike locks) all a lock is doing is stopping someone quickly and idly opening your locker without fiddling with it and *hopefully* someone noticing they’re trying to break or bypass the lock.
This is one of those “picture is worth a thousand words” situations, so [here you go](https://commons.wikimedia.org/wiki/File:Pin_tumbler_with_key.svg).
In pin-and-tumbler locks, the key works by moving the pins so you have a straight line between red and purple pins that lines up with the line between the yellow and green cylinders. Until you get that all lined up, the pins are in the way and stop the yellow piece from rotating.
That explanation out of the way: The yellow and green bits are easily mass produced. The springs are easily mass produced. The purple and red pins are mass produced in a variety of sizes. The part that varies between locks is just choosing a random-ish assortment of pins, and cutting the key to match the pins, and even that is fairly simple to mass produce.
While you can’t have infinite variations of pin setups, you do have several thousand different keys for the same lock type, so randomly stumbling into an identical key is fairly unlikely.
As others said, they aren’t. I can’t remember the exact key code, but a lot of places tend to have their fused box lock be the same. It was like CS137. So if you had a CS137 key, you could get in.
I used to have a lot of fun as a teenager getting into places I should be then turning off their breakers.
Standard keys were used for cars as well up until about a couple of decades ago. I remember 2 of my friends had similar cars, and the door keys unlocked each other’s doors, but the engine keys were different and did not swap.
When I worked at home Depot there was like max 6 different types for home door locks. Most only had two or three different key versions. Many people can possibly unlock your home just by knowing the brand of knob you have. Pretty neat
I’m assuming you are referring to standard pin key locks. There are actually a lot of youtube channels that can explain it far better than I, but the basic gist is that you have a cylinder, lock pins, and driver pins. In an industrial mass production environment, you have machines making pins of each size. All the pins are interchangeable, and it really easy to cut keys at separate depths.
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