07 March 2019

Elaborate warded lock

Found at the mildlyinteresting subreddit.
These are called warded locks. If the key wasn't the same shape as the ward, the lock wouldn't open. Older versions were pretty easy to pick by modern standards, but wards are still in use. Modern locks have a plate on the front of them that defines the shape of key that the lock will accept. That's why you need to get a key cut from the appropriate blank or it won't work. If you check your keys, odds are very good that stamped on the bow (the part of the key that you hold to turn it in the lock) is a small letter/number code that identifies the blank and therefore the shape of the ward.
Source: Former institutional (i.e. corporate) locksmith.
Warded locks are an old type of lock where the key has to pass over several obstructions (wards) as it rotates, before it can engage with the mechanism and unlock. It doesn't refer to the shape to which the blank must conform (the shape of the keyway), but the shape to which the final key must conform.

You are correct regarding warded locks using internal wards to stop a key from rotating unless it was the correct shape (unless it was a skeleton key, which bypassed these internal wards). But using that definition for a ward is too narrow. Wards are physical obstructions that stop the key from entering or turning the lock.

If the ward stops the key from entering the lock, it's a keyway ward. In the lock, they're the protrusions from the keyway that necessitate the grooves that are cut down the length of the key. They partly define the shape of the blanks (in addition to other things like the number of pins in the cylinder). The cuts on the blade of modern keys are generally there to align the shear line on internal pins to open the lock and are therefore not associated with wards. Exceptions to this would be for things like control keys on interchangeable format cores, which allow the lock to be removed from the door with the simple turn of a key (great for swapping out office locks). I've also seen some modern padlocks, cubicle cabinet locks, and the like that use internal wards, but they're generally low quality.


  1. Reddit always has the most informed, insightful comments (if you are patient enough to wade through the dumb jokes and memes).
    I would love to see a list of the subreddits (mildly interesting, showerthoughts) that you find have quality discussions.

    1. I agree with your assessment of Reddit. As the author of an "accumulator" blog, it was a godsend for me to discover Reddit years ago simply because of the variety of material available there. And I appreciate that there is at least a modicum of monitoring and curating.

      I don't routinely monitor subreddits, because the front page provides an abundance of material (and has no bottom...) My problem with TYWKIWDBI is not finding material, but finding time to blog.

      I have bookmarks for Murdered by Words, Design Porn, Madison Wisconsin, History Porn, Documentaries, Conspiracy, Data Is Beautiful, The Way We Were, Artefact Porn, autotldr, and most recently Interesting As Fuck.

      Probably the best discussions are on politics-related subjects, but of course they trend toward the left of center (at least the ones I encounter).

  2. both of those key plates looks like stick figure people!



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