Steam-hammer. A forging machine in which the hammer is raised or lifted by steam, and is sometimes also forced downwards by steam.

Steam-space. That part of the boiler that is above the level of the water.

Sticker. A machine that operates on wood of small cross-sectional area in proportion to its length, such as picture frame moulding.

Stock. Material.

Stocks-and-dies. Tools for cutting external threads by hand.

Stop. 1. A piece that arrests the motion of another piece. 2. A part of a gauge, against which the work abuts.

Stop-motion. A device for preventing the overwinding of clocks and watches.

Straddle-mills. Milling-machine cutters that are used in pairs and straddle the work, both cutters being of the same diameter.

Straight edge. A piece or strip having one or both edges made straight to use as a guide in testing work.

Stub end. The end of a connecting rod.