Definition
A specialized woodworking hand plane used to cut a square-bottomed groove (a dado) across the grain of a wooden workpiece. In aircraft construction, it was historically used during the fabrication of wooden airframe components, ribs, and structural members where precise joinery was required.
Plain English
A hand tool that cuts a flat-bottomed slot across a piece of wood. The slot it cuts is called a dado, and the plane that cuts it is called a dado plane.
Context Anchor
Seen in wood aircraft construction, restoration, and repair discussions, especially with older or vintage aircraft.
Derivation
Dado comes from the Italian word for 'die' or 'cube,' originally referring to the cube-shaped block at the base of a column. In woodworking, it came to mean a square-cut groove. A plane is a hand tool that shaves wood. So a dado plane is simply a plane that cuts a dado.
Why Pilots Care
Clean, accurate dado joints produce strong, lightweight wooden structures that maintain alignment and load-carrying ability under flight stresses.
Intuition Check
Do not read plane here as an aircraft. A dado plane is a woodworking tool, and the dado is the rectangular groove it cuts.
Example Sentence 1
The restorer used a dado plane to cut clean grooves in the spruce ribs of the antique biplane wing.
Example Sentence 2
After marking the fuselage longerons, a few careful passes with the dado plane produced the exact depth needed for flush gusset plates.