Name for lock parts: pins or tumblers?

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Trying not to screw things up worse
Jan 6, 2017
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Oh Hah
Up until today I thought the moving parts inside a lock, the things that need to line up just so if you want to turn the key and open the lock, are called "tumblers". But after someone said they didn't know what tumblers were I second guessed myself and looked up "lock diagram" on DDG to see how diagrams referred to these parts. All the diagrams on the first page of my search referred to them as pins instead. I 've seen that before too but it's not as salient to me as tumblers.

Then I thought, where did I get tumblers from? So I did another search for "lock tumblers" and then found a bunch of diagrams referring to what looked like those same parts as tumblers!

Now I'm really confused. I figure either:
1. It's a British/American English thing that I somehow missed
2. They refer to functionally similar parts used in different kinds of locks, and I just didn't notice the difference
3. The terms are interchangeable

Can anybody shed light on this?

(Also, admins, creating this thread made me realize we don't have a board for something like "locks, cameras, and home security systems", which is an area of DIY it's easy to imagine people having questions about.)
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Lifetime Supporter
Lifetime Supporter
Sep 30, 2006
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My understanding is the difference between a lock that is accessed via a keyway, and a cylindrical lock that is accessed via a rotating cylinder which in tern allows tumblers to align, allowing access.

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