Definition
The smooth, cylindrical portion of a twist drill that fits into the chuck or drill holder. It is the part of the drill that is gripped by the drill motor or drill press, as distinguished from the fluted cutting portion that does the actual drilling.
Plain English
The plain end of a drill bit — the part the drill machine grips onto. It's the opposite end from the cutting tip.
Context Anchor
Seen during aircraft maintenance when selecting, installing, or tightening a drill bit before drilling holes in metal, plastic, or composite parts.
Derivation
Shank' comes from Old English 'sceanca,' meaning leg or shin — the straight, supporting part of something. The drill's shank is its 'leg' that holds it in place while the business end does the work.
Why Pilots Care
Mechanics and owner-builders need to match drill shank size to chuck capacity. A shank too large won't fit; a shank that's worn or damaged can slip during drilling, causing oversized or off-axis holes — a real problem in structural work where hole tolerances matter.
Intuition Check
The shank of a drill is not the sharp cutting part. It is the held part that goes into the drill.
Example Sentence 1
Before tightening the chuck, he made sure the shank of the drill was seated straight to avoid a wobbly hole.
Example Sentence 2
A worn or oily shank can cause the drill bit to slip under load during sheet-metal work.