The metaphoric expression “fly off the handle” is an Americanism that goes back to pioneer days when frontiersman whittled their own handles and attached axe heads to those handles. The axe heads were shipped from the industrialized East coast which meant that if a frontiersman wasn’t much of a carpenter, the axe head may not be as securely attached to the handle as one might hope it would be.
Because of this, axeheads were known to “fly off the handle” while being used and if anyone was nearby, there was a fairly good chance that either the bystander or the axeman would be injured by the flying axe head.
The expression was recorded in John Neal‘s 1825 novel Brother Jonathan as “off the handle.” The version of “fly off the handle” happened in Canadian author, Thomas C. Haliburton‘s book The Attaché also known as Sam Slick in England, which was published 18 years later in 1843.
Historically Speaking 