What generation is this 4251-20?


Here is a 4251-20 that I got in a lot of 5 4251-20s for parts some years ago. Which generation is it?

Most of it points to the supposed-2nd-generation (I’m not sure how many generations there are), but the lock confuses me as I’m not sure I’ve ever seen a 4251-20 with that kind of lock: reminds me of some 4251-20s that I have that for some reason had their locks replaced with ones from supposedly a piece of furniture of all things (or at least that’s what the key that works with them comes back to when I search the name on it).

Here’s the inside of another one if this helps

That’s a 2nd gen 4251

Thanks! Any info on the lock design?

It’s a regular cam lock, appears to be manufactured by Hudson. It uses the cat 30 key

What do the Locks normally look like?

Like the ones on most 4251-20s you can find a picture of via Google.


Like this

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Ahh thanks for the clarification.

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I wonder if this is some early experimental 4251-20? Or if it’s an undiscovered generation of a 4251-20?

Definitely not a first gen…

Now the thing is, why some 4251’s have that lock and why they seem to be a lot rarer than the ones with regular locks

Thats a 2nd gen 4251

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Definitely a second generation, we take care of a local school, built in 1974, that has 4251-20 with that style of lock,