Seller taper to Sepia
tom, equal to one eighth of the pitch. The included angle is 60 deg.
Sellers taper. (Mach.) The taper is 0.75 inch per foot. It is not as much used as the Brown and Sharpe or the Morse tapers.
Selvage. (Textile) The edge of cloth running lengthwise and parallel to the warp and formed by the return of the filler yarn in weaving.
Sema-phore. An apparatus, with movable or stationary arms for giving signals.
Semi-chord. Half the length of the chord of an arc.
Semi-circle. A half circle, bounded by the circumference line and diameter.
Semi-circular arch. (Arch.) An arch whose intrados is a half circle.
Semi-elliptic spring. (Auto.) As indicated by the name, the shape of this spring is approximately that of half an ellipse. It is much used on automobiles.
Semi-floating axle. (Auto.) The outer ends of the axle shafts are carried in bearings and the inner ends by the differential side gears. The wheels are keyed to the tapered outer ends of the shafts. Formerly a broken shaft meant the loss of a wheel.
Semi-positive mold. (Plast.) A mold which allows a small amount of excess mate~al to escape when it is closed.
Semi-rigid airship. (Aero.) One whose form is maintained by a rigid or jointed keel and the internal pressure in the gas containers and ballonets.
Semi-steel castings. (Metal.) Produced by adding soft steel or wrought iron scrap to the charge in the cupola. These castings are made in the same manner as ordinary castings. They are used for machine parts, large gears, etc., where both strength and finsih are essential. The usual amount of scrap in the mixture is about 20 per cent. The carbon content of the finished product runs about 3 per cent.
Semi-trransparent. Translucent, allowing the passage of light, but not permitting a clear view of any object.
Sensible beat. (Engin.) Heat which is measured by the thermometer, as opposed to latent heat.
Sensitive drilling machine. (Mech.) Those designed for operating small drills of about Y.z in. and under, at high speed.
Separable plug. (Auto.) A spark plug so constructed that it can be disassembled for cleaning or repair.
Separately excited. (Elec.) A machine which gets the current needed for the excitation of its field from some source outside of itself.
Separators. (Auto. Elec.) Used as insulators between the plates of a battery. They may be of wood or special composition, and must be porous to allow circulation of electrolyte.
Sepia. (Color) Dark brown tinged
Septic tank to service tank with red.
, Septic tank. (Plumb.) A plumbing unit used for decomposing solid sewage matter. It is designed to dispose of these wastes in a completely sanitary and odourless manner by natural bacterial action which dissolves most of the solids into liquids and gases.
Sequence. In regular order, or systematic arrangement. ,
Serial taps. (Mach.) A set of taps usually numbered I, 2 and 3 No. I is a tapered tap, No.2 is slightly tapered near the end, and No.3 is a fullthreaded tap, called a "bottoming" tap.
Series. (Elec.) When two or more pieces of electrical material or apparatus are so connected that the current feeding one must pass through the others, they are said to be in series. (One after another, as in a string.) (Print.) A quantity of type of the same style in a number of sizes and faces.
Series dynamo. (Elec.) A direct-current dynamo in which the armature and field are connected in series internally.
Series motor. (Elec.) A direct-current motor with the armature and field connected in series. Used on elevators and other machines where variable loads occur. The 'speed varies with the load.
Series parallel circuit. (Elec.) A circuit made up of two or more simple parallel circuits all joined in series.
Series wound. Noting a commutator in which the field circuit and armature circuit are connected in series.
Series welding. A resistance-welding process wherein two or more welds are made simultaneously by a single welding transformer with the total current passing through every weld.
Serif. (Print.) A light line or stroke crossing or projecting from the end of a main line in a letter.
Serrate. Notched on the edge like a saw.
Serration. Like the toothed edge of a saw.
Service. (Elec.) That part of an electrical installation between the pole transformers and the meters and their associated equipment.
Serviceable. Useful; capable or be ing of service..
Service ceiling. (Aero.) The height above sea level, under normal air conditions, at which a given airplane ce'ases to be able to rise at a rate in excess of 100 feet per minute. This specified rate varies in different countries.
Service ell. (Plumb.) An elbow having an outside thread on one end.
Service pipe. The small pipe which
|
