Where does this come from, and can I check it?

Each key cut raises one lever until its gap lines up with the bolt. The figure is taken from Encyclopaedia Britannica, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.

Is this really a everyday life fact?

Yes. It sits on the Everyday Life shelf, one of 2,600 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.

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The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.

Mondo Knows Facts

Lever locks open only when every lever is lifted

Each key cut raises one lever until its gap lines up with the bolt Inside a lever lock, several small levers pivot on a post, each with a slot called a gate. The right key lifts each lever to exactly the height where all the gates align, freeing the bolt. A key cut too high or low leaves one lever blocking the way, which is why lever locks tolerate far fewer key variations than pin locks. It sits in Mondo's everyday life collection, one of 200 facts that each trace back to the reference below.

Where this comes from

Encyclopaedia Britannica

Facts that can change over time are reviewed and updated. If something here looks wrong, Mondo would rather know than be confidently incorrect.

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Technology trivia General Knowledge trivia

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Master keys work with extra pins in the lockTwo shear heights per chamber let one key open many different locks Cylinder pin-tumbler door locks align split pins along a shear lineKey ridges lift spring-loaded split pins to unlock door cylinders Door key notches act as mechanical physical passwords for locksGround key blade cut depths lift internal door pins to the exact shear line A deadbolt has no spring, unlike a door latchThe latch slides back by spring and bevels to close, but the bolt does not Long door cylinders can be snapped at the middleThe weak point sits where the lock body meets the handle plate Combination locks release when internal notches line upEach dial turns a disc with a gap, and all the gaps must meet at once

Tags: locks, keys, mechanics

Lever locks open only when every lever is lifted: the short answers

Where does this come from, and can I check it?: Each key cut raises one lever until its gap lines up with the bolt. The figure is taken from Encyclopaedia Britannica, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.
Is this really a everyday life fact?: Yes. It sits on the Everyday Life shelf, one of 2,600 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.
What else can I read about it?: The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.