Factor of Safety. When a calculation of the ultimate strength of a machine is to be made it is necessary to provide for contingencies—this takes the form of a multiplier, and is called the factor of safety, or the margin of safety.
Feather, or sunk key. A key that is fast in one piece of work, and an easy fit in the other, as a feather in a shaft.
Flow. Motion of a fluid or liquid in one direction. “Flow-gate“ is a term sometimes applied to a riser.
Flume. An open trough for conveying water.
Gate Valve.
Globe Valve.
Gate Valve. A valve which opens the full area of the pipe, on the principle of a gate in a water flume.
Globe Valve. A valve having a round ball-like shell as shown in the engraving.