Definition
A hand file with a rectangular cross-section that tapers slightly in both width and thickness toward its point. Both flat faces are cut with teeth and are used for general-purpose filing of flat surfaces and edges on metal.
Plain English
A standard metalworking file with a flat, rectangular shape that gets a little narrower and thinner toward the tip. It is used to smooth or shape flat metal surfaces.
Context Anchor
Seen in aircraft maintenance, sheet-metal work, repair procedures, and tool lists.
Derivation
From the shape of the tool: 'flat' refers to its rectangular cross-section with broad flat faces, distinguishing it from round, half-round, triangular, or square files used for other shapes of work.
Why Pilots Care
Mechanics and builders use flat files routinely to dress edges, remove burrs, and fit parts. Choosing the correct file shape affects the quality and accuracy of the finished work.
Intuition Check
Do not read flat file here as a computer file or a paper folder. In this maintenance context, it means a physical hand tool used to remove or smooth material.
Example Sentence 1
The mechanic used a flat file to smooth the edge of the aluminum bracket after cutting it to size.
Example Sentence 2
After trimming the bracket, he finished the surface with a flat file to achieve the correct fit.