Definition
A machine tool used in aircraft sheet metal and structural work to produce a flat, smooth surface on a workpiece by feeding the work past a stationary single-point cutting tool, with the work mounted on a reciprocating table that moves back and forth beneath the cutter.
Plain English
A shop machine that shaves a metal part flat by sliding the part back and forth under a fixed cutting blade, taking off a thin layer with each pass.
Context Anchor
Seen in aircraft wood-structure maintenance and repair, especially when preparing wooden parts before fitting or bonding them.
Derivation
From the verb 'plane,' meaning to make level or flat, which itself comes from the Latin 'planus' meaning flat or even. The machine is named for what it does: it produces a plane (flat) surface.
Why Pilots Care
If a wooden aircraft part is planed unevenly or made too thin, it may fit poorly or lose strength.
Analogy
Think of a deli slicer running in reverse: instead of moving the blade across the food, the food slides back and forth under a fixed blade, shaving off a thin layer each pass.
Intuition Check
Do not confuse planer with planner, which means a person or tool that makes plans. A planer is a cutting tool or machine used on wood.
Example Sentence 1
The technician used the planer to true up the mating surface of the steel block before reinstalling it.
Example Sentence 2
Before installing the new rib, the builder used the planer to bring the capstrip to exact thickness.