Gear-wheel. A wheel provided with teeth to engage with similar teeth upon another wheel.

Generating-circle. The circle that is supposed to move in the construction of cycloidal curves.

Gib. 1. A piece that may be set up to take up the wear. 2. A piece for holding a strap, and forming an abutting piece for a key.

Gimlet. A wood-boring hand tool, having a threaded conical end to pull it to its cut.

Gimlet-bit. A fluted gimlet having no thread at its end, but a spiral flute so shaped as to pull the bit forward to its cut.

Gland. A piece enveloping a stem and used to make a tight working joint.

Globe-valve. A valve, having a spherical body, used in pipe-work.

Goose-neck. A frame affording a fulcrum for a ratchet brace.

Gouge. A wood-cutting hand tool that is curved in its cross-section.

Gravis. A hand tool, rectangular in cross-section and having cutting edges at its end that are formed by grinding the end face at an acute angle to the body of the tool.