If you cut something in half, do you get two parts or two pieces? Do they convey different meanings? This is in the context of a mechanical part physically cut in two.
closed as too localized by JSBձոգչ, Robusto, Matt Эллен, RegDwighт♦ Mar 6 '12 at 16:02
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In the context of a mechanical assembly, I would understand 'part' to refer to a component or subassembly which might have been dismounted from the whole, while 'piece' would be an arbitrary fragment, e.g. that resulting from a straight cut or break.