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I have acquired a chest for which the key was lost years ago. Since I don't want to destroy the lock or the chest, I try to find out what key I need. The chest and key are of german manufacturing as far as I know and as far as the previous owner told me, at worst 150 years old as his grandmother bought it new.

enter image description hereenter image description hereenter image description here

I took a few measurements:

  • Key shaft diameter ca. 9 mm
  • Key centering pin ca. 2 mm
  • Key bit length ca. 14 mm, biggest thickness ca. 9 mm
  • Lock is about 25 mm behind the brass plate

The brass plate seems fully ornamental - removing the screws did change nothing. It appears to me that the lock is mounted to the chest from the inside. It seems to follow some german standard that apparently is still used. Assuming there are no cuts in the key needed, what is the correct keyway numbering?

  • Hello, and welcome to Home Improvement. Did you try unscrewing those flat-head screws to get at the inside? And, you should probably take our tour so you'll know how best to participate here. – Daniel Griscom Oct 18 at 16:48
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    I'm voting to close this question as off-topic because there is no realistic way to provide an answer to the question. – Jimmy Fix-it Oct 18 at 17:08
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    I don't remember enough off hand for a proper complete answer right now, but that is not a complex lock, and fabricating a makeshift key/picking it seems reasonably practical. - Question: Can any parts be shifted by poking them with something? – TheLuckless Oct 18 at 17:15
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    Small hex keys AKA Allen wrenches are great for stuff like this. It looks like the security of this lock depends more on the odd shape of the keyhole than on any internal complexity. – Wayfaring Stranger Oct 18 at 23:39
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    @FeRD 1) nope 2) the hinges seem to be piano-hinges mounted inaccessible from outside. – Trish Oct 19 at 17:42
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According to a german key manufacturer catalog, this is a Drilled, Corrugated bit (Buntbart) with about 14 mm bit length and unknown bit height. It seems to fit a larger variant of Keyway 7 of a "Möbel- und Truhenschlüssel":

enter image description here

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    I'm no locksmith, but getting a couple of these blanks would be a good start. They should go in the lock and start to rotate a bit. Use some bluing ink on the paddle of the key and when it presses on a block in the lock, will leave a mark. Then OP should file some material away at that point - perhaps a couple of square mm. Re-blue and repeat. Do remember the key may rotate left or right to undo. – Criggie Oct 19 at 4:02
  • @Jasen I disagree. The images show some of the interior structure of the lock. #7 matches the visible interior structure and would also fit the wear pattern in the brass plate. – Makyen Oct 19 at 4:25
  • Keys like this are actually used in Germany today; my room key looks very much like the one you're going to need, except for the hole in the center of the round part. The online vendor www.zimmerschluessel.de (I have no affiliation with them whatsoever) offers you to upload a photo so they can find the correct key for you, they should be able to help. As they aren't intended to be highly secure, this kind of key generally doesn't have any notches, the shape alone is what prevents every key from matching every lock. – Guntram Blohm supports Monica Oct 19 at 6:00
  • @Makyen from the catalogue mentioned: The direction of sight is from the bow to the bit. The pictures represent the key hole. – Trish Oct 19 at 8:53
  • @Trish Thanks. It's good to confirm that. I should have explicitly stated I was assuming those drawings were looking from that orientation, rather than that the drawings were looking at the bit end-on (i.e. bit to the bow). Looking at the interior of the lock in the first and second images in the question, it appears clear there's an outline of the flipped Z through which the key must be inserted, IMO. – Makyen Oct 19 at 14:40
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Those locks nearly always have multiple wafers/levers/tumblers that match specific notches that are cut into the key; these are not visible from the outside.

So even though the necessary key profile is discernible in the pictures, there is no way to tell what particular key cut will work. If it was so easy then the lock would be pointless as anybody could just look at it and produce a key.

You need a locksmith. Alternatively, someone who is good at picking locks could perhaps get the chest open, then you could remove and replace the lock with a new one.

Different people/cultures/countries/crafts all use different names for that TYPE of key. I call it a hollow barrel cabinet key, which is as good a type name as any.

People who are experienced with various types of locks and keys, e.g. picking locks, cutting and crafting keys, rekeying locks etc., know that what you ask is not as simple as you may think. The picture below shows the TYPE of key you need but the size and location of the tooth at the end, along with the number and size of the slot(s) cut into the tooth, are what determine whether or not it will open the lock. There are literally hundreds (thousands?) of possible configurations...

enter image description here

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