Are there repeating keys by now?

[Chromite297]

Hey guys, got a question and didn't know where else to put it.

There could be a billion locks by now which means billions and billions of keys. Using a standard deadbolt house lock as an example, how can they make a different key for every single lock? It seems to me like they'd have to start using the same key and tumbler combinations. If I buy a deadbolt front door lock in California, could it have the same key as someone in Kentucky? I've wondered about this for a a while now and figured this is a good forum to ask it. Thanks.

[Divinorum]

Hey guys, got a question and didn't know where else to put it.

Using a standard deadbolt house lock as an example, how can they make a different key for every single lock? If I buy a deadbolt front door lock in California, could it have the same key as someone in Kentucky?

Short answer. Yes, it is impossible for every lock to have an absolutely unique key. There are a lot of possible combinations for keys, but there are more locks produced and in existence than there are possible key combinations. It is a guarantee that key bittings will be used more than once. I have seen locks on the shelf at home depot all take the same exact key. They are not intended to be keyed alike the stock was just put out this way.

Sure it's entirely possible for a key you buy in California to work in Kentucky or anywhere else. Will it likely happen? I don't really think so. There are so many possible pinning combinations that your chances of having a random key open a random lock are very slim.

[GWiens2001]

Yes, there are millions of locks with the same key. Think of it this way... Master lock has 8 depths and four pins for most of their locks.

8x8x8x8 = 4,096 possible key permutations, including keys that exceed MACS (Maximum Adjacent Cut Specifications). The actual number is lower than that. Yet Master Lock makes many thousands (hundreds of thousands?) of locks a year.

Kwikset has six depths and five pins for their normal home deadbolt lock.

6x6x6x6x6=7,776 permutations, again including those that exceed MACS. They must sell a million of those locks a year.

Better locks tend to have better bittings and more pins. But yes, hundreds of locks have the same keys as your home. Unless you go with something a little more unusual, like a KABA, EVVA, DOM or ABLOY.

Even then, how many people are going to have the 1/4000 chance of happening to have the same Master lock key on them? Unless they pick locks, in which case they always have the right key.

Gordon

[averagejoe]

There are certain locks like the Kaba 20 which could technically NEVER (well a really long time) have a duplicate key in existence.
http://www.kaba.com/access-control/en/products-solutions/mechnical-lock-cylinders/332590/kaba-20.html

Permutation capacity (theoretical number cylinder differs): 726 billion

Given that some of those are not possible due to MACS etc, there are still several times the number of possible different keys than there are people on Earth.

[Legion303]

This works the same way for car keys, too. Sleep tight.

[somenewguy]

Just wanted to make it clear to the OP that the 'matching key' issue would only be within the same keyways; for example, if you have a Kwikset lock and your neighbor has a Schlage lock, the keys wont fit from your key in his lock and vise versa (usually) because of the design of the keyway shape (warding). Not sure if that was part of the question.

[GWiens2001]

This works the same way for car keys, too. Sleep tight.

Back in the late 80s, my dad asked me to take the van home and get something that my mother forgot. I was visiting from out of town, and he just handed me the keys. Told me it was a white Voyager with blue interior.

Took the keys, went out to the parking lot, got into the white Voyager with blue interior, drove to his house, got the sweater, drove back, and parked in the lot again. After he finished what he was doing, we walked out to the parking lot, and he went right up to a different white Voyager with blue trim!

Gordon

[cledry]

Oh it happens. I once went to rekey a business that I had never been to and grabbed a random key from a supply of originals I keep and it just happened to be the same as the existing key. I've been doing this sort of work for over 30 years and I can count on one hand the number of times it has happened, so it isn't a common occurrence.

[Squelchtone]

The worst thing is big box stores like Home Depot or Lowes. I went in to get a Schlage deadbolt to mount on a practice board and I wanted some good bitting. I must have went through probably 10 or 15 packages that were all keyed the same! Since your neighbors are also shopping at the local Home Depot, just buy one of those deadbolts and you may just have a key to a house in your neighborhood. now that's scary!

Squelchtone

[Legion303]

The worst thing is big box stores like Home Depot or Lowes. [...]

The moral of this story is "screw big box stores, support your local locksmith."

[GWiens2001]

The worst thing is big box stores like Home Depot or Lowes. [...]/quote]

The moral of this story is "screw big box stores, support your local locksmith."

+1. You get better service, better locks, and keep a type of business in business.

Gordon

[dll932]

This works the same way for car keys, too. Sleep tight.

Back in the late 80s, my dad asked me to take the van home and get something that my mother forgot. I was visiting from out of town, and he just handed me the keys. Told me it was a white Voyager with blue interior.

Took the keys, went out to the parking lot, got into the white Voyager with blue interior, drove to his house, got the sweater, drove back, and parked in the lot again. After he finished what he was doing, we walked out to the parking lot, and he went right up to a different white Voyager with blue trim!

Gordon

For many years auto makers repeated code sequences every few years.

[serrurier]

I guess how locks are made at the manufacturer is paramount. One can only hope that each lock made at the source is not the same as the previous one. If this is the same then you find yourself in a situation as was described before which is the person in front of you buying his lock the same as yours may have the same key profile.

Unfortunately, when all you care about is profit you will maximize your production by making the same thing in multiples then you will change it. This means that most locks in the same shipping box will most likely be the same and should be shipped to the same region etc. I tend to not be as optimistic with the people stating that it is unlikely to find the same key around.

However, how many people drive around with hundreds of keys just in case? You might as well just pick the lock.....

Keep on picking

[dll932]

I guess how locks are made at the manufacturer is paramount. One can only hope that each lock made at the source is not the same as the previous one. If this is the same then you find yourself in a situation as was described before which is the person in front of you buying his lock the same as yours may have the same key profile.

Unfortunately, when all you care about is profit you will maximize your production by making the same thing in multiples then you will change it. This means that most locks in the same shipping box will most likely be the same and should be shipped to the same region etc. I tend to not be as optimistic with the people stating that it is unlikely to find the same key around.

However, how many people drive around with hundreds of keys just in case? You might as well just pick the lock.....

Keep on picking

Automakers used to sell trial sets: A big ring of keys you could use to pretty much open any car they sold. I remember a local mall where police caught people trying to use them to steal cars.

[somenewguy]

Lockpick supply houses used to (and probably still do) sell Ford and GM tryout key rings. This obviously only helps you open the door and start the car if it was a pre-VATS type system with no RFID or other electronic magic in the key bow.