Definition
A machining operation in which a hole is enlarged and finished to a precise diameter by removing material from its inner surface using a single-point cutting tool. Boring produces a hole that is more accurately sized, rounder, and straighter than the original drilled or cast hole.
Plain English
Making an existing hole bigger and more accurate by shaving material from its inside walls with a cutting tool.
Context Anchor
Seen in aircraft maintenance and overhaul descriptions, especially when parts must fit together accurately.
Derivation
From the Old English 'borian,' meaning 'to pierce' or 'make a hole.' In machining, it kept the meaning of working a hole — but specifically enlarging and refining one rather than creating it from solid material.
Why Pilots Care
Engine cylinders are bored to precise dimensions during overhaul. Knowing the term helps a pilot or owner read engine logbooks and overhaul reports, where 'bored to oversize' indicates the cylinder walls were machined to fit larger pistons or rings.
Intuition Check
Boring does not mean “dull” here. It means cutting or finishing an existing hole to a precise size or shape.
Example Sentence 1
After inspection, the shop recommended boring the cylinders to the next oversize before reassembling the engine.
Example Sentence 2
After boring, the cylinders accepted the oversize pistons with proper clearance for safe operation.