Greave to Grinding in

Greaver to Grease trap
Graver. A tool used by engravers. I
Gravity. That force which draws all bodies towards the center of the earth or to its surface.
Gravity ceU. (Elec.) A modified form of Daniell cell in which the two electrolytes are separated by gravity.
Gravity~rop annunciator. (Elec.) A signal device operated by electro­magnets which release a catch peritting a hinged part to fall, reveal­ing a number, name, etc.
Gravity lubrication system. (Auto.Mech.) Feeding oil to parts to be ubricated by gravity from an levated tank or reservoir. Such sys­terns are frequently equipped with a ump. to return oil to its original contamer.
Gravity water system. Any water sys­tem in which pressure is obtained by gravity.
Gray iron. Pig or cast iron which, on being fractured shows a gray crystalline structure.
Grease gun. (Auto.) A device for forc­ing lubricant into a bearing.
Grease lubricants. Gillet divides grease into six classes: (1) the tallow type, a mixture of ~Iow and palm PIp oil with some mineral oil; (2) the soap- thickened mineral-oil type; (3) type I or 2 mixed with graphite talc, or mica; (4) the rosin-oil type; (5) nonfluid oils; (6) special greases with special filters.
Grease trap. (Plumb.) A device for solidifying and separating grease from domestic wastes and retaining the same so that they may be re­moved. Its purpose is to prevent the stoppage of waste pipes.

Green to Grinding in

Green. Colour between yellow and bluew in colour spectrum. (Paper­mkg. and Print.) Term applied to paper and printing rollers indicatig incomplete seasoning. .
Green core. (Fdry.) A core that has not been baked.
Greenfield.. (Elec.) The original trade name for flexible conduit.
Green gold. (Chern.) An alloy of 25 per cent silver and 75 per cent gold.
Green sand. (Fdry.) Foundry sand moistened with water and not dried.
Green sand core. (Fdry.) A core made of green (Le., moistened) sand.
Green vitriol or copper-as. (Chern.) A by-product from the pickling of steel; also known as "ferrous sul­phate." It is important as a disin­fectant, and in the manufacture of ink, Prussian blue, and red oxide.
Green wood. Timber from which the sap has not been removed by sea­soning and drying.
Grid. (Elec.) An electrode having one or more openings for the passage of electrons or ions. (I) Heavy resistances used in connection with the fields of generators. (2) The foundation on which the plates are
formed in storage batteries. (Plast.) A parallel, channel-shaped, cast-iron support, a number of which hold the steam plates away from the press platens during knockout operations and also provide air spaces between plates and platens to reduce loss of heat. (Radio.) Part of a radio tube, usually between a filament or heater and the plate.
Grid condenser. (Radio) A condenser which is a part of the grid circuit.
Grid leak. (Radio) A resistance used in the grid circuit of an electronic tube.
Grid resistance. (Elec.) Starting resistances for very large d.c. mo­tors are made of cast iron in the from of grids.
Grid resistor. (Radio) A high resis­tance used in the grid circuit of a radio tube.
Grille. (Arch.) An openwork of metal or wood, plain or ornamental, used to cover an opening, or as a protec­tion over the glass in a door or window.
Grind. To sharpen, to reduce to size, or to remove material by contact with a rotating abrasive wheel.
Grinder. (Shopwk.) Any appliance or device on which work in done by grinding.
Grind finish. (Mach.) A finish imparted by an abrasive wheel. A great deal of the work is now fini­shed by grinding that was formerly tool finished.
Grinding allowance. The amount of material left on a piece of work to allow for a finish by grinding. On fine work .003 to .007 in. is suffi­cient, while on heavy work it may be 1/64 or 1/32 in.
Grinding compound. (Auto.) A grease and abrasive or water-carried abra­sive used in valve-grinding opera­tions.
Grinding in. (Mach.) Bringing to a perfect fit of parts, which are to

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