HI! I'm new and I have a question. THANKS!

[lasholly]

Hi,

I'm new to this site, and I'd be very grateful if someone can answer a question.

I'm writing a screenplay about a locksmith, and this is why I need the information.

My primary question is how many different lock and key possibilities are there? This may sound like a stupid question but here's why I ask.

Many years ago several friends and I parked in a public parking garage and then went to a show. When we came out, the gate was down and we couldn't get to our cars. A person we were with said, "don't panic. there are only like 7 (or 10 or maybe he said 70. I don't remember now) different keys in the world." He then took all of our key rings and tried them in the lock. Sure enough one of them worked and the gate opened and we got to our cars.

This has stayed with me and, over the years, I have tried my keys in various locks when I needed access to a place (never illegally) and a few times, my keys have worked.

So this is part of my story. A woman learns from this locksmith that you should always try your keys if you get locked in or out of someplace. Is this common knowledge? What is the likelihood that one's keys will open more than one lock? Is this plausible?

Thanks so much to anyone who can give me any info about this.

[atticRR]

hmm, interesting. not only are there so many different kinds of locks, but within those lock brands are many different keyways, meaning one brand lock will have many keys that only fit into that lock. next is the number of combinations that can be set up within the specific lock with the specific keyway. the likelihood that a random key will work in a lock is pretty low in my opinion- the fact that you had it work on the rare occasion you needed it is amazing. there are people way more knowledgeable than me here that will probably say the same thing as me but with some numerical examples to back their statements.

there are so many locks and keys. i have scads of keys and i have tried them on different locks i own-just to see if i would get lucky-and it hasnt happened yet. regardless, there are more then seven, ten or seventy keys in the world-a lot more.

[2octops]

There are thousands and thousands (if not millions) of different keys and locks in the world. You have to consider the number of vehicles, motorcycles, padlocks, residential, commercial, high security, safe, cabinet and furniture locks in the world. We stock over 1,500 different key blanks in our inventory and we still have customers come in with keys that we've never seen before and new keys are being added each year.

However, if you are in Texas then you will likely not run across a lock that is common in Russia or even Europe so that will rule out a bunch. If you are trying to open a padlock, then you will not likely try your car or house keys, so that rules out a bunch as well.

Even with a single manufacturer, there are thousands of combinations per keyway. Some keyways will pass others and some locks have loose enough tolerances that you can be off by a good bit and the key still works.

I've been locksmithing for a very long time and almost every lockout I do, I just stick a random key in the cylinder to see if it will work. Very few times has this ever actually happened, but it has happened. There are more locks produced per keyway than there are available combinations, so there will always be another lock somewhere with the same key.

For example, one of the Ford code series only has 1706 different combinations. Ford used that code series for 16+ years. I can assure you that Ford produced much more than 1706 different vehicles over that time period. So, in theory, if you had one random key for this series and tried it in 1706 different Ford vehicles that used that series, you'd have a pretty good chance that your random key will fit at least one of the vehicles that you tried.

[MacGyver101]

What is the likelihood that one's keys will open more than one lock? Is this plausible?

That question can really be answered in two ways, and it depends entirely on what you're thinking of when you say "more than one lock". Let me try to expand on 2octops' answer a bit for you, in the hopes that it helps...

I have a fairly large collection of different makes and models of locks. If you were to go through all my boxes of locks, trying every key you own on all 200+ locks, I can pretty much guarantee that you wouldn't be able to open any them: having any of your keys work on any of the locks would be on par (in terms of probability) with winning the lottery.

Now, your question could be taken a slightly different way (and this is exactly what 2octops was referring to). When a manufacturer makes a particular model of lock, there is a limit to the number of different keys that could possibly exist for that model (and poorer lock designs tend to have fewer possible keys)... so, if you take your key for your Ikea filing cabinet and try it in someone else's Ikea filing cabinet, there is an excellent chance it will work. Some keys work in more than one model or brand of lock... so your Ikea filing cabinet key may also happen to fit and open the lock on the shredding bin at work -- but it's far less likely. In contrast, the key to your Toyota isn't going to even fit into a filing cabinet lock, let alone open it.

It's getting a bit late -- so this probably isn't the best analogy -- but instead think of the sort of search that hospitals do when they're looking for matches for donors (e.g., bone marrow donors, etc.). It's very likely that one of your siblings will be a match, it's possible that your uncle might be a match, and it's very unlikely that the next stranger who walks into the room will match at all.

It's the same with your key question: the chances are pretty good that your Ikea filing cabinet key will open the next Ikea filing cabinet you see, it's unlikely (but not completely impossible) that it might fit into the switch of the next elevator you ride and let you put it in "service mode" or turn the lights out or something... but your Ikea filing cabinet key will definitely will not start your BMW.

Hope that helps...

[maintenanceguy]

In a word: many thousands of different possibilities.

-Hundreds of different manufactures
-Each manufacturer has dozens of different keyways (the shape of the uncut key viewed from the end)
-Each keyway takes a unique key blank (uncut key). A few keys will fit in more than one keyway - sometimes by design and sometimes by accident but most often there is one key blank shape made to fit one keyway shape.
-Each key blank will have 3-6 "cuts" (somebody's going to correct me and say that locks can have more or less - true but unusual). "cuts" are the V shaped notches on the edge of the key blank after the blank is cut.
-Each cut can have between 6 and 9 different cut depths (same disclaimer - a few odd ones have more or less)

If we're only talking about building entry locks (not padlocks, not vehicles, ect.) and sticking only to US locks, My very, very rough estimate is:

200 manufacturers x 25 keyways each x 5 cuts on an average key x 6 possible cut depths on an average key = 150,000 different keys. There are more than 150,000 locks so once in a while you could get lucky.

[Squelchtone]

While everyone is giving you good answers with the number of possible combinations and talking about different keyways, let me say it this way: In 10 years of trying keys on my keychain in locks I encounter that I needed to get into, it has only happened two times. Once I noticed my friend's housekey, a Schlage SC1 was the same exact cuts as my parent's Schlage SC1 key that was on my keychain, and the other time was at work where I noticed that my data closet Schlage SC1 key would open the maintenance wood shop, SC1 door knob, but the maintenance guy's shop key would not open my data closet. I believe my data closet key had almost the same cuts except for one, and it was close enough to the shop key that if i jiggled my key up and down it would lift that last pin high enough to open their lock. Note that in progressively pinned up buildings, keys will be very similar except for one or two of the key cuts, and my data closet door was 20 feet from their shop door, so I'm sure my key cuts were 90% similar based on the buildings master key system and progressive pinning chart.

Other than those 2 times in 10 years of trying my keys in other people's locks, that's the only time that happened. Whatever gate you guys opened at a parking garage years ago must have been the best luck ever, you should have played the Powerball that night..

good luck with the play, sorry if it isn't exactly what you were hoping to hear,

Squelchtone

[i_b_larry]

Some twenty years ago I rented a storage locker on the second floor of an oddly shaped building. There were hallways in every which direction and getting to my locker required that I navigate a maze. On one trip to my locker I made my way through the maze, arrived at my locker, opened my lock, and realized that nothing in the locker belonged to me! I stepped back and saw that my locker was next to the one that I just opened with my key.

I closed the wrong locker and went to the hardware store for another lock. I knew my key would open the other guy's locker and I wanted to be sure that he did not find out that he could open mine. We were both using Master laminated padlocks and I have never used one since then. I figure if you have a Master padlock that there are at least a million other people out there with a key that will open it.