How come Key A can open Lock A. Key B can open Lock B. But not lock A. And key C can open all the locks? Doesn’t that mean A and B should be able to open each other?
In: 731
you might have heard of “lockpicking lawyer” you might have heard of “Devient Ollam” (“Ollaf”).
if you havent, go binge some stuff, i feel like you would enjoy it.
[https://www.youtube.com/watch?v=aVPSaKLKHd4](https://www.youtube.com/watch?v=aVPSaKLKHd4)
Are master keys not called skeleton keys anymore? Sorry if this is a stupid question, but I always liked the designation “skeleton key”. Or is that only for buildings?
You want to cleanly bite off a piece of carrot.
You have seven teeth top and bottom to do the job.
Each tooth needs to meet the tooth above or below for a successful bite.
If any one tooth is too long, it will hit the upper tooth before the other 6 teeth finish biting. Fail
If one tooth is too short, 6 teeth will finish biting but the 7th tooth doesn’t reach the shorter tooth. Fail.
Now consider drilling a tooth size hole through the carrot.
Now when you bite, 6 teeth will bite properly and the long tooth doesn’t matter because there’s no carrot there due to the hole. The bite just needs 6 teeth for a good bite.
It’s the carrot that made the difference with the hole.
Oh, Hell! I’m not five yet and I can’t take this to conclusion.
Will eat an apple instead.
Locksmith here.
In a standard household lock, there are usually 5 chambers that hold 5 sets of a top and bottom pin. When the key enters the lock, it raises these sets of pins to each particular height so that the space between the top and bottom pin lines up with the turnable part of the lock (the shear line). If even one of those sets doesn’t line up properly, the lock cannot turn.
A master keyed lock works by having a top, bottom AND middle pin in at least one chamber. This makes two different lines in the chamber. Meaning 2 different keys can raise the pin to 2 appropriate heights, since there are two spaces.
A master (or middle) pin in all five chambers exponentially increases the number of different keys that will work in each lock, though it is still common practice to have all three pins in each chamber, even if you only want one extra key to work.
Determine master key possibilities, numbers etc gets a bit complicated and requires above an ELI5.
Also, how do keys work?
So, the shape of the key, and the parts inside a lock correlate to a numbered code. Physical math. In fact, your key may have it’s code written on it, usually 5 or 6 digits.
A number like 6, could also be 4+2.
So you have two locks, each with five pins (numbery bits)
[6] [6] [6] [4+2] [6]
[6] [4+2] [6] [6] [6]
Now, we have 3 keys, A, B, and Master.
Key A is [6 6 6 4 6]
Key B is [6 4 6 6 6]
You could then have a Master Key coded to [6 6 6 6 6] that would open both. And yes, there are a couple other combinations, like [6 4 6 4 6] that would also work. It’s a little more complex/precise than that, but that’s the idea.
Because of that, setting up doors for a master key system makes them much easier to pick as there are multiple succesful paths, with it getting exponentially so with each extra key/lock you’re tying in.
Depending on the lockset, different pins of varying heights are used. The master key is set to work with the initial pin configuration, followed by the other keys interacting with the additional pin discs used to build them.
I used to build locksets for our medical facility. We had three master lock setups: one for the main facility; one for the pharmacy (and related storage areas); and one for the mental health wing. Even though I’m not a locksmith, I performed the function of a locksmith, including using lockpicks to open cabinets that the staff had lost keys to. I never tried to open safes though.
ELI5 answer:
Each pointy edge on the key is made to push a little metal pin out of the way so the lock can turn.
Some locks may use different pins in different spots.
A lock with small pins in the front would need a key with small edges near the handle.
A lock with large pins in the back would need a key with large edges near the end.
A key with large edges near the end and small edges near the handle could open both locks.
(It’s actually more complex than this, but this is the idea simplified)
Locks have pins in them that when aligned properly, the lock can turn. In each slot, there’s a driver pin and a key pin. Each one will a different length, determining how the key has to be cut to open the lock. When the gaps between the pins are all aligned with each other and the edge of the part of the lock that turns, called the shear line. When all of that lines up, the lock can turn.
[Visual explanation](https://thumbs.gfycat.com/AcceptableAccomplishedAfricangoldencat-mobile.mp4)
If you want a master for those lock, in-between the driver and key pins (in at least one slot) you add what’s called a master wafer. This adds another break between the pins, meaning there’s a different combination distances to push the pins that also opens the lock. To have several different locks that all open to the same master, ideally you would have all the pins but one be the same, and then the last pin has a different sized master wafer in each lock such that the master key fits all of the locks.
For example I’ll use arbitrary numbers for pin lengths:
1, 2, 3, 4
1, 2, 3, 5
1, 2, 3, 6
Each one needs a unique key, but if we give each one a master wafer in the last spot of lengths 3, 2, 1 respectively
1, 2, 3, 4/7
1, 2, 3, 5/7
1, 2, 3, 6/7
Each one’s unique key still works, but a key for 1, 2, 3, 7 will fit all 3 locks
ELI 5:
To open the lock you must rotate a gear to pull back the bolt.
The gear doesn’t want to rotate because there is a pin that has dropped down a chute and blocked the turn. Push it up out of the way, and the gear will turn.
To lift the pin, you insert a key to push it up and out of the way.
This is what most old style locks were. Simple, but effective for most uses. However this is a very easy to beat lock. Push the pin up far enough and the lock opens. No real challenge.
The solution is to make it so pushing up to far also locks the gear in place. So the locking pin is now 2 pins sitting on top of eachother. Push it up just far enough that the break point is on the border of the spinning section and the stationary section and the key/gear will turn. To far up and the bottom pin binds. Not far enough and the top binds.
This is most modern locks.
Master Keyed locks have 2 breaks. So 3 pins.
The first break is for the normal key, and is unique to each lock. (or perhaps a small set, like “storage closets”)
The second break is identical across all locks in the set, and is the master key. (this would be all doors in the building)
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