Throw-line. The travel of a piece, moved by an eccentric.

Thumb-nut. A nut so shaped that it may be screwed up or unscrewed by hand.

Tight. A term used to denote those parts of a plate or saw that are under undue tension, and prevent the other parts of the plate from lying flat.

Timber-planer. A wood-planing machine for thick work, usually having side heads as well as cutter bars.

Tire. The iron band surrounding a wheel rim.

Tit-drill. A drill having a point or teat, and employed to cut flat-bottomed holes.

Tool-post. The device employed in a slide-rest to grip the cutting tool.

Train. An arrangement of gear wheels in which there are more than two gear wheels employed.

Trammels or tram. A device for measuring distances too great to be measured by ordinary compasses.

Trip-hammer. A forging machine in which the helve or hammer holding beam is tripped by a revolving cam.