This precision gauge, which is also called an indicating gauge, consists of a plunger that has gear teeth cut along parts of its length to engage a gear on the indicator needle to provide a visual indication of even very slight variations in the grade of a surface. The gauge, which has a needle that passes around the precise dial, which shows gradations as small as one ten-thousandth of an inch, is tightly clamped to a rigid surface, then the plunger is adjusted to connect with the work which is to be measured. This work is then moved past the plunger, which provides readings of the variations in the surface. When precision measurements, such as centering a piece of work in an independent chuck on a lathe, this gauge is valuable.
Dial plate
Trim piece found behind a single-control wall-mount faucet handle. Also known as a face plate.
Diameter
Distance of a straight line passing through the center of a circle or sphere from one side to the other.
Diamond
Mineral consisting of almost pure carbon in crystalline, which was formed under pressure and is the hardest natural substance known.
Diamond drops
Droplets of sap that appear on the surface of painted wood.
Diamond point chisel
Metal cutting tool for cutting V-shaped grooves or to make sharp corners in holes by use of a V-shaped cutting edge.
Diaphragm
(1) Any partition or membrane separating one thing from another. (2) Thin, flexible disk that vibrates in response to sound waves, producing electrical signals or vibrates in response to electrical signals, producing sound waves. (3) Structural sheathing, which may be applied over framing; between the webs on a bridge crane girder, acting as a load-bearing unit.
Diaphragm action
On a structure, a stressed skin, which resists movement, by providing stiffness that could distort the structural square, shape.
Diaphragm tank
Partitioned expansion bank with the gas and water separated so that no gas can be absorbed into the water system.
Diaphragm valve
Valve which is used for fluid control or for shutting off pipeline fluids or gasses from coming in contact with the operating parts of the value, due to the threaded stem which forces a compressor plug against the diaphragm.
