Righty-tighty, lefty-loosey (or lefty-loosey, righty-tighty) is a catchphrase and a sort-of nursery rhyme designed for educational purposes.
The goal of the rhyme is to help recall the mechanics of a conventional screw, bolt, or nut that operates with threads.
When rotating a screw clockwise (right-way), it tightens. When rotating it counterclockwise (left-way), it loosens. Hence the rhyme.
The exact origin of the expression is currently unclear.
According to redditor u/logantauranga, the direction for turning wood screws to tighten them was formalized in England in the late 18th century, which was when wood screws were first mass-produced.
This would indicate that the expression was coined subsequently to the 18th century.
It is such a universal and well-recognized expression that it really did not need a platform to spread on. It is used as a generic advice in the most basic fields of mechanical engineering and workmanship.
Righty-tighty, lefty-loosey often appears in pop-culture as well, like in the 1983 film Fandango, which features Kevin Costner in his first leading role. A dialogue features a character saying: “The other way, bud. Remember, it’s lefty-loosey, righty-tighty.”
- Todayshomeowner.com – Righty-Tighty and Lefty-Loosey