OT combination safe and tumblers

[micky]

OT In the movies, safe-crackers are always listening to the tumblers in the bank vault door. Sometimes they use a stethoscope.

Does that really work?

Decades ago I had a plastic toy safe, with transparent door and walls, and it opened with a combination too. But there were no tumblers to listen to. By turning a 2 full turns to the right and a little more to the first number, then to the left a full turn and a little more to the second number, and to the right to the 3rd number, the notches in the rotating disks were aligned, and when the 3rd number was reached, the third disk, which was a little bigger than the other two, allowed the lock lever to move into all three notches at the same time. Maybe I'm not clear here, but trust me, there were no intermediate noises.

So if they can do that for a toy safe, worth no more than $5 now, why wouldn't they do that for a bank vault?

[Stormin Mormon]

Short answer: yes, a stethoscope is totally helpful.

I worked for a locksmith, who taught me a bit about safes. He had electronic stethoscope, which was beyond excellent.

Christopher A. Young Learn more about Jesus

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Does that really work?

Decades ago I had a plastic toy safe, with transparent door and walls, and it opened with a combination too. But there were no tumblers to listen to. By turning a 2 full turns to the right and a little more to the first number, then to the left a full turn and a little more to the second number, and to the right to the 3rd number, the notches in the rotating disks were aligned, and when the 3rd number was reached, the third disk, which was a little bigger than the other two, allowed the lock lever to move into all three notches at the same time. Maybe I'm not clear here, but trust me, there were no intermediate noises.

So if they can do that for a toy safe, worth no more than $5 now, why wouldn't they do that for a bank vault?

[micky]

Well, to you and 'ormin, it seems like a mistake to make a safe one can get into by listening, when it's possible and not expensive, it sure seems, to make on where listening doesn't help. I don't get it.

[The Daring Dufas]

Heck, just put a Classic Big Ben wind up alarm clock in the safe as a click sound jammer and keep it wound. ^_^

TDD

[trader4]

I would guess that it would work with some safes, depending on how they were implemented. In your example, if you applied pressure to the lock lever, would you not hear a difference in sound when any one of the rotatitng disks with a notch came up and the edge of the slot touched the lever?

[bud--]

That is how I understand stethoscopes work.

I doubt it works on a good dial lock. One way to defeat it on a crappy lock is to have the driven disk kind of like a coarse gear. And for smaller modern safes the bolt is withdrawn by the dial. There is no handle that applies pressure against the disks.

[gfretwell]

I have actually had an old Mosler apart retrieving a lost combination. It was locked but open I am not sure what you would hear. It really looked like a better machined Master combination lock. There were disks with slots in them and a pawl that you could cam into the slots if they all lined up. I did not see anything that "dropped" or otherwise indicated when a slot was under the pawl and the machining was so tight that you couldn't feel the slot until the last one lined up. I think the dial locked when you rotated the unlock handle so you couldn't "hunt".

[dadiOH]

Why bother when it is so easy to make nitroglycerine?

[Bill]

In general Hollywood is not very understanding of technical things or REALITY. The people who write those movies can't change a tire on their car - city people.

For example as shown in movies, a heart defibrillator does NOT start a stopped heart!...

And I have yet to see a computer which makes the noises "movie computers" do.

Also they show crooks jumping a couple of wires on a burglar alarm and then it is disabled. This is NOT going to happen in real life. The people who work at the alarm companies could not do this, let alone a burglar.

Then safes and vaults are designed differently and are of different quality so far as their ability to deter thieves. The better of these are "U.L." rated. And the better rated take more "time" to break ["These requirements cover combination locks intended for attachment on doors of safes, chests, vaults, and the like, to provide a means of locking the boltwork against unauthorized opening. These requirements are intended to test the ability of combination locks to resist unauthorized opening of the combination locks by sense of sight, touch, or hearing. Combination locks covered by these requirements may or may not have integral protection against entry by force."]

[Wes Groleau]

Or has ten zillion blinking lights and parts that explode/catch fire when you type in an insoluble problem.

[Stormin Mormon]

I'll explode if I have any more thanksgiving pi.

There seems to be no end.

Christopher A. Young Learn more about Jesus

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Or has ten zillion blinking lights and parts that explode/catch fire when you type in an insoluble problem.

[gfretwell]

It is easy to make nitroglycerine, the trick is not setting it off while making it.

I often wonder how long a regular residential or medium price safe would hold up to a cutoff saw with a diamond blade.

[Jim Elbrecht]

or the harbor freight "twitchin' tool" [TM by Heybub].

Jim

[trader4]

What's a crock is the premise of that link. In my experiences of watching movies, for example, they don't use CPR on someone who's clearly been dead for a day. They use it on anyone where there appears a chance that it will work. Are you saying for example, that lifeguards or first responders would NOT perform CPR on someone who was missing for 15 mins and then found in the surf?

And as for the defibrillator, again, I don't see it being used to try to revive someone dead for a day. It's used for the most part like it is in real life. And no claim in any of the movies I've seen has been specific to the point that they talk about exactly how it works.

There are indeed lots of stuff in movies that is nonsense. But this link sure isn't good at finding it. Half of them are wrong.

[Bill]

With many of those home safes, they can simply carry it out of the house and take their sweet time breaking into it elsewhere. So the weight of the safe or that it be encased in concrete is another factor.

Then if the safe can't be moved, a monitored burglar alarm would limit the time they would have to break into it. And a "U.L. high security rated" burglar alarm would be the best quality alarm.

[micky]

Exactly. In the case of my toy plastic safe, the tolerances were not fine or tight at all, and it was totallly clear that nothing happened until the 3rd number was dialed.

Esactly.

That sounds good. The toy safe didn't have this. ;-)

[micky]

I don't remember if there was an locking/unlocking lever. I think one just pulled on the dial or a fixed piece to open the door, But the thing with the pawl didn't/couldn't move at all until the last number was dialed and the first two disks with slots werel 1/8 to 1/4 inch away from that.