to Jack rafter
Jack. (Mech.) A mechanical device used for lifting heavy loads through short distances with a minimum expenditure of manual power. (Tel.) Female receptacle for a plug (male type connector).
Jack arch. (Masonry) The ordinary flat arch; also called "French arch:'
Jack Bay. Also known as a patch bay, a jack. bay is a panel containing a number of signal jacks (usually standard phone jacks or mini phone jacks). Jack bays are commonly used in studio recording consoles and in equipment racks, they serve to provide the user with flexibility in re-routing signals (beyond that provided by nonnal switches or controls). The jack bay alsQ offers convenience when temporarily connecting certain equipment to the system, or troubleshooting.
Jack, electric. A fonn of metallic spring contact, connection being made by inserting a plug which is attached to a cord. Commonly used on telephone switchboards and radios.
Jacket. (Mech.) An outer casing, as around a boiler or tank, to preserve heat or cold, or around a motor cylinder, pennitting a flow of water to prevent overheating.
Jack, hydraulic. (Shopwk.) Device for raising weight or exerting pressure by pumping oil or other liquid under a piston or ram.
Jacking up. The raising up of masses of machinery and heavy structures by means of jacks.
Jack, leveling. (Shopwk.) Small jacks (usually screw jacks) for levelling and holding work on planer beds and similar places; practically adjustable blocking.
Jack plane. (Woodwkg.) A plane used for roughing off, bringing the wood down to approximate size. after which it may be finished with a foreplane or a smoothing plane.
Jack Plug. The male part of the world's most common audio connection, it connects to the Jack Socket. Available in two types, mono and stereo, the jack system can either be a dual or triple termination connector.
Jack rafter. (Bldg.) Short rafter with one end tenninating against a hip or valley rafter. When one end terminates against the hip .and the other against the valley rafter, it is often tenned a "cripple:'
Jachscrew to Jetty
Jackscrew. (Mech.) Small screw jacks' for levelling work in jigs.
Jacobean. (Furn.) Of or relating to the time for James I of England. That style of architecture or furniture popular in England during the early part of the seventeenth century.
Jamb. (Arch.) One of the upright sides of a doorway or a window frame.
Jam nut. (Mech.) Same as lock nut.
Jam plate. (Shopwk.) Old name for screw plate and in many cases a true one, as the thread was jammed instead of cut. ;
Japan. (Wood Fin.) In the painting trade a drying agent.
Japan drier. Has no relation to baking japan which is baked on a surface giving a beautiful enamel-like finish. Japan drier is composed of linoleates, a salt of linolenic acid (CI7H29C02H), or resinates of lead or manganese, usually containing free oil and often some resinous varnish, and dissolved to a thin liquid with turpentine or benzine; added to paint in small quantities to hasten drying.
Japanning. (Pail/t.) A method of finishing wood or metai with baking varnish or baking japan, usually applied by dipping, after which it is baked at varying temperatures, on wood at low heat, but on metal at from 300 to 400 deg. F.
Jardiniere. (Fum.) An ornamented wooden, earthenware or metallic bowl for flowers or plants.
Jamo taper. (Mach.) This taper of 0.6 inch per foot is used by a number of manufacturers for taper pins" ,sockets, and shanks used on machine tools.
Jarring machine. (Fdry.)A, moldi~ machine used for ramming molds by a jarring motion. Also called a jolting machine.
Jaw chock. A lathe chuck consisting of a faceplate equipped with adjustable jaws. A chuck may be universal, 'in which all jaws move together, or independent, in which each jaw is adjusted separately.
Jeff. (Print.) A game played with emquads thrown in the same manner as dice. The person throwing the greatest number of quads with the nick up wins the game.
Jenson. (Print,) A Roman type face named after Nicolas Jenson, a French printer who introduced this face of type during the fifteenth century.
Jet. (I) A spout or nozzle. (2) That which spurts out.
Jet aircraft. (Aero.) Aircraft or airship (usually a fixed wing airplane) powered by one or more aid b~ealhing jet engines.
Jet engine. (Aero.) Any engine that ejects a jet or stream of gas or fluid, obtaining all or most of its thrust by reaction of the engine.
Jet molding. (Pfast.) A continuous molding operation for thermosetting materials characterized by fully preheating the composition before it is injected, and rhythmical control of heat.
Jetty. (Nam.) A structure of stone or wood, projecting into a body of
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