Groove-cam. A cam in which the actuating surface is in the form of a groove.
Ground joint. A joint that is finished by grinding the parts together, usually with oil and emery.
Guide-bar or slide-bar. A bar that forms a guide for the crosshead of an engine or other moving piece.
Gum. 1. The bottom of the space between saw teeth. 2. A rubber-like substance formed of oil that has dried.
H
Hack. A tool used for cutting iron in two under a steam hammer.
Hack-saw. A saw held in a frame and used by hand for cutting metal.
Half-check joint. A joint in which a piece is let into the other, so that the surfaces come level.
Half-round file. A file that is half round in cross-section.
Hand-file. A superior class of file that is parallel in width and thickest in the middle of its length.