Machinist Apprentice Level One Practice Test

Metals form a solid crystal lattice that fills the entire piece, so they are a uniformly solid material in bulk. The atoms are arranged in a repeating pattern, giving a continuous solid with a consistent density and mechanical behavior throughout the volume, even though there are grain boundaries and defects at small scales. This uniform solid nature is what lets machinists cut, shape, and gauge metals with predictable results. One notable exception is mercury, a metal that is liquid at room temperature, so the statement wouldn’t apply to mercury itself; for typical metals worked in shops, the bulk is solid.