A tongue-in-cheek label for the part of a tool or machine that injures hands: the closing jaws of a vise, a spinning chuck, a bandsaw blade, a hinged guard or a ratchet that snaps back. Calling something a thumb detector is a warning disguised as a joke, and the term often comes with a story about who found it first.
Heard on the job
Watch the clamp arm on that fixture, it's a thumb detector, keep your hands on the outside of the plate.
Also heard as
- finger detector
Related terms
Chuck key
The T-handle wrench that opens and closes a geared drill chuck or lathe chuck, never left in the chuck.
Safety squints
Shop slang for squinting instead of wearing eye protection, and jokingly for safety glasses themselves.
Persuader
Shop name for a hammer, usually a big one, used to convince a stuck part to move.