Hi everyone!! I collect antique and vintage keys, and I am here to talk about them!! Because... I want to :D
Rather than just showing off my collection and leaving, I'll add some more substance to this too by including trivia about keys!!
Here's a group photo to start off with. This isn't actually my entire collection, as some of it wandered off a few years ago and I still haven't figured out which box they're in :P

And before you ask: yes, that strange one at the bottom right IS a key! A lock and key set, in fact:

When you slide the knife into the snake's perch, the lock opens, and when the dagger is removed, it closes! Unfortunately, the internal mechanism that controls the lock's movement has gotten bent out of shape over time, so while you can easily take the knife out (aka, lock the lock), it's actually pretty tricky to stick it back in (unlock the lock)! But it's such a gorgeous piece, isn't it? And so creative; someone had fun designing it!
Antique keys (for reference, "antique" is generally defined as "over 100 years old", while "vintage" is usually considered "over 20 years old") have three parts to their anatomy: The bow, the shaft, and the bit. The bow is the flat "head" of the key-- the part you hold in your hand. The shaft is the body of the key, and the bit is the teeth at the end!
Back in the old days, locks were way less fancy than they are now, and obviously they didn't have fancy electronic systems or anything.
If you were creating locks and keys for a hotel, or a factory, or an office building, or any place where some people have limited access and others have full access, it would be way too awkward for the owner to have to carry around a ring of 100 different keys. Enter: the skeleton key!
The locks back then, like I said, were pretty simple. They were mostly basic tumbler pin locks, where the pattern of the key's teeth pushes a row of interior pins into the correct alignment which allows the lock to turn. So in those buildings, they would make all the locks very similar, but not quite identical-- they would add extra little flourishes that made each key match a certain lock. But then, they would make a master key that had none of those extra flourishes, only the bare essentials to meet the basic lock pattern. And because it didnt have extraneous sticking-out parts, that master key would be able to work any lock in the building! That's why they're called "skeleton" keys, because all the extra parts are stripped away, leaving only the most minimal skeleton of the key.
Now, granted, locks were pretty garbage 300 years ago, and there were only so many different pin/bit patterns, so oftentimes thieves could just carry around a bunch of generic keys from different smiths, and occasionally one of them would just randomly be close enough to work in the lock they were trying to get through!
These days, while still not perfect, our locks are much more secure. If you look at vintage or modern keys, you'll notice that their anatomy has changed: the shaft and bit have merged into a single segment, called the "blade". The bow/shaft/bit vs bow/blade distinction is the easiest way to identify a key made in the last 100 years!
Keys nowadays also have grooves along the flat sides of the blades, which match up to patterns in their locks to prevent the old "carry 10 keys and hope one works" trick. It doesn't matter whether the teeth can coincidentally push the pins into alignment, if you can't even get the key to fit into the keyhole in the first place!
Alright I'm running slightly out of steam so I'm gonna pause here for now. I have SO MUCH to say about keys, but it'll have to wait til morning at least :P
If anyone else has any cool keys, or any interesting key trivia, I'd LOVE to see/hear about it!!
(Remember: if you're gonna share a photo of a key, make sure there's no identifying information on the key or otherwise in the photo! Info about where the key came from is fine, obviously, but don't say or show anything that could reveal where you are or jeopardize your security!!)
Feel free also to ask me about/comment on the keys I showed from my collection!! I will have more to say about them after I get some sleep either way, but I'd love to hear anyone's thoughts/answer anyone's questions!!! ^w^