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

The tapered cross pushes the driver out before it can over-tighten the screw. The figure is taken from US Patent and Trademark Office, 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

Phillips screw heads were meant to let drivers slip

The tapered cross pushes the driver out before it can over-tighten the screw Henry Phillips patented the cross recess in the 1930s, and its sloping flanks deliberately cam the driver outwards once the screw is seated. On a moving assembly line that stopped powered drivers from stripping threads. The later Pozidriv adds four extra ribs so the bit grips without that slip. It sits in Mondo's everyday life collection, one of 200 facts that each trace back to the reference below.

Where this comes from

US Patent and Trademark Office

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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Tags: tools, screws, manufacturing

Phillips screw heads were meant to let drivers slip: the short answers

Where does this come from, and can I check it?: The tapered cross pushes the driver out before it can over-tighten the screw. The figure is taken from US Patent and Trademark Office, 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.