Allen screw definitions

Allen screw

[n] - a screw with a hexagonal hole in the head
Found on http://www.webdictionary.co.uk/definition.php?query=Allen%20screw

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Allen screw

noun a screw with a hexagonal hole in the head
Found on https://www.encyclo.co.uk/local/20974

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Allen screw

a screw turned by means of an axial hexagonal hole in its head.
Found on https://www.infoplease.com/dictionary/allen-screw

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