Short to Shrink rule
support. Also the timbering used to prevent a sliding of earth adjoining an excavation.
Short. (Plast.) Marks on the surface of a molded article indicating incomplete filling of the mold.
Short circuit. (Elec.) A path of low resistance placed across an elec trical circuit causing an abnormal flow of current.
Short length. (Wood.) Refers to lumber less than eight feet in length.
Short nipple. (Plumb.) Shoulder nipples are referred to as long or short nipples depending on the length of blank space between the threaded ends.
Short pouring. (Fdry.) When the metal in the ladle is not sufficient to completely fill the mold.
Short-time duty. (Elec.) That demand which requires operation at a constant load for a definitely specified short time.
Short ton. Two thousand pounds.
Shortwave radio. Radio reception or transmission employing high-frequency radio energy in the form of short waves as a means of communication.
Shot. (Plast.) The yield from one complete molding cycle.
Shoulder. (Mech.) That portion of a shaft, or of a stepped or a flanged object, where a sudden increase of diameter occurs.
Shoulder nipple. (Plumb.) A nipple of any length which has an unthreaded portion of pipe between the two threaded ends.
Shoulder screw. (Mech.) Acts as a:pivot pin for levers. The shouldered portion must be slightly longer than the hub of the lever through which it passes in order to avoid binding.
Shoulder stud. (Mach.) An easily removable threaded stud used for mounting levers and other parts.
Show card. (Print.) A large advertising card such as is.often dIsplayed in store windows.
Show rafter. (Arch.) A short rafter, often ornamented where it may be seen below the cornice.
Shrine. (Arch.) (1) A receptacle of sacred relics. (2) A tomb or chapel.
Shrinkage. (Fdry.) The failure of a casting to retain its exact size, weight, and shape during the process of cooling in the mold. Shrinkage is much greater in large castings than in small.
Shrinkage crack. (Fdry.) Crack in a casting caused by unequal cooling of its pans.
Shrink fit. (Mech.) A tight fir accomplished by heating a colloar or like part, and permitting it to cool in position; made tight by contraction.
Shrink holes in castings. (Fdry.) Cavities caused by unequal cooling. They frequently occur in thick parts of castings which have sudden changes in dimension. .
Shrinking. (Mech.. Fdry.) Drawing together; contracting; diminishing.
The contraction of a casting in cooling.
Shrink rule. (Patmkg.) The rule used by pattern makers when making
Shroud to Side slipping patterns in order to properJy aUow for the shrinkage of the metaJ in which the pattern is to be cast.
Shroud. (Mech.) A flange cast against, or attached to, the ends of gear-wheel teeth in order to increase their strength or to promote smoothness of motion.
Shrouded wheels. (Auto.) Wheels almost enclosed, on streamline automobiles, by means of side skirts on the fenders.
Shroud line. (Aero.) The suspension cords of a parachute which attach the harness to the canopy.
Shunt. (Elec.) UsuaUy a comparatively low resistance connected in parallel, with, or across a device or part of a machine.
Shunt for ammeter. (Elec.) A predetermined known resistance connected in parallel with the galvanometer; used to limit the current through the meter. An ammeter is basically a glavanometer connected in parallel with a known resistance.
Shunt generator. (Elec.) A machine for generating an electric current, in which the winding for producing the magnetic field is connected in shunt, or parallel, with the armature or rotating part.
Shunt-wound motor. (Elec.) Used when the motor speed must be constant, irrespective of variation in load. .
Shutter. (Photog.) A device for controlling duration of light through a camera lens.
SID. Audio 'information' handled by equipment as alternating voltages or currents, whether directly as
. audio or as modulati~n on carrier. More commonly Slew Induced Distortion.
Sidebands. Frequencies other than that of the pure carrier wave necessarily added to RF carrier when modulation is present.
Side bars. (Plast.) Projections used to core a hole in a direction other than the line of closing of a mold, and which must be withdrawn before the part is ejected.
Side head. (Print.) A heading set to one side instead of centered.
Side-milling cutter. (Mach.)" Cutter of comparatively narrow face which cuts both on the periphery and the sides. When two or more cutters are set up on an arbor, they are called "straddle mills."
Side rake. (Mach.) The amount of transverse slope away from the cutting edge on the top face of lathe, planer, shaper tools, etc.
Siderite. (Metal.) FeC03. An ore of
low iron content.
Side slipping. (Aero.) The opposite of skidding when it occurs while turning. When the lateral axis of the airplane is inclined and a slipping takes place in the direction
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