Plate 106Larger plate.
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1855. Bevilled flat iron.
1856. Trough iron.Used for bridge flooring, fire-proof floors, &c.
1857. Double convex iron.
1858&1859. Tramplate iron.
1860&1861. Chair or sleeper iron.
1862. Oval iron.
1863,1864, &1865. Round edged flats.
1866. Segment round iron.
1867. Round edged convex iron.
1868. Bevilled flat iron.
1869. Bevil edge flat iron.
1870. Bevilled flat iron.
1871. Round edged hollow convex iron.
1872. Taper edged hollow convex iron.
1873. Boiler tube expansion ring iron.
1874. Moulded flat bar.
In addition to the above, iron ornamental mouldings are rolled with moulded and relief ornaments in bars, from5⁄8″ to 23⁄4″ wide, and up to 16′ or 18′ long. Also plain mouldings similar in sections to those used in joinery.
Plates(iron and steel) are manufactured from1⁄8″ to3⁄4″ thick ordinary. Thicker plates are rolled to order up to 20″ thick.
Stocked sizes of ordinary plates are 4′ × 2′ up to 14′ × 4′ 6″.
Stripsfrom 7″ to 22″ wide, and up to 30′ long.
Chequered plates,with diamond, oval or square recessed patterns, are made 6′ × 2′ up to 8′ × 3′ 6″.
Sheets,plain, in thicknesses from No. 10 w.g. to No. 36 w.g., and from 6′ × 2′ to 10′ × 4′.
Corrugated sheets, plain or galvanised, from No. 16 to No. 26 w.g., and from 6′ × 2′ to 9′ × 2′.
Tinned sheets, same as above.
Cold rolled sheets, same as above.
Planished sheets, same as above.
Lead-coated sheets, same as above.
Tin plates, terne plates, 14″ × 20″, 17″ × 121⁄2″, 15″ × 11″, 14″ × 10″, 24″ × 20″, 28″ × 10″, 28″ × 20″.
Hoops,from5⁄8″ to 7″ wide, and from No. 8 to No. 24 w.g.
1875. Wire; sections manufacturedin hard iron, soft iron, soft steel, hard steel, tempered steel, piano wire, covered wire (wound with either cotton, silk, guttapercha, flax, &c.), or copper wire. Also brass, copper, lead, zinc, and other metal wire, hard or soft; tinned iron wire, galvanised iron wire, tinned brass wire, coppered iron wire, lead-coated iron wire.
Plate 107Larger plate.
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Pipes(seeSection 57)and tubesof wrought iron, either butt or lap welded, or solid drawn, are made in four qualities or strengths:—1. Gas tube; 2. Steam or water tube; 3. Boiler flue tube; 4. Hydraulic tube. These are manufactured from1⁄4″ to 3″ internal diameters; boiler flue tubes to 9″ diameter, but much larger sizes can be made to order.
Solid drawn steel tubes are made up to 10″ diameter; larger sizes are made to order.
Special steel or wrought iron pipes, flanged withLiron, are made up to 4′ diameter with welded joints, and welded steel or wrought iron socket and spigot pipes up to 24″ diameter.
Cast iron pipesare made in the following strengths:—Rainwater pipes, hot-water pipes, gas mains, water mains, hydraulic mains for high pressure, and the thicknesses of metal vary according to the pressures. Diameters from 11⁄2″ up to 4′, and lengths usually 6′ and 9′. SeeSection 57.
Castingsare made in cast iron of various mixtures, according to strength, toughness, or hardness required, and of any weight up to 20 tons. Chilled iron castings are made for hard wear, as in crusher rolls, &c., but cannot be machined; they are usually ground smooth by a grindstone or emery wheel.
Steel castingsare made in either Bessemer, Siemens-Martin, Thomas-Gilchrist, or in crucible steel, the latter being most relied upon. They require annealing to soften them sufficiently for machining, are almost invariably “blown” or honeycombed, and rarely homogeneous, or twice alike from the same pattern or cast.
Wrought-iron castings,Mitis metal, &c., are also obtainable, but malleable cast iron castings are most relied upon for toughness, the process having now attained great perfection, but is not applicable to very thick castings.
Pressed iron on steel forgings of simple forms are now obtainable at low prices.
Forgingsin wrought iron and steel can now be made to almost any size, shape, and weight, and are replacing many structures formerly made of cast iron or built up.
Other metalsemployed are copper, brass, tin, zinc, phosphor-bronze, lead, antimony, bismuth, pewter, Muntz metal, aluminium, sodium, potassium, platinum, gold, silver, nickel, and a great variety of the bronzes, which are valuable compounds varying in tenacity and hardness from the hardest steel to that of soft copper. Most of the above are manufactured into wire, sheets, tubes, rods, &c., and can in addition be cast into any form from a crucible. Copper can be forged but not welded; joints in it are generally brazed or soldered.
Other materialsemployedcomprise—
Timber.Yellow, white, and red pine in logs, deals, and battens; logs, up to about 3′ diameter by 35′ to 40′ long; deals, 9″, 10″, and 11″ wide, and from 11⁄2″ to 4″ thick—a few wide deals are imported up to 22″ wide—spruce and fir, sycamore, pear tree, willow, poplar, &c. The following table gives a list of woods and theirapplications:—
Ship-building.—Cedars, deals, elms, firs, larches, locust, oaks, &c., &c.
Wet works, as piles, foundations, &c.—Alder, beech, elm, oak, plane-tree, white cedar.
House carpentry.—Deals, oaks, pines, sweet chestnut.
Frames, &c.—Ash, beech, birch, deals, elm, mahogany, oak, pines.
Rollers, &c.—Box, lignum vitæ, mahogany.
Teeth of wheels, &c.—Crab-tree, hornbeam, locust.
Foundry patterns.—Alder, deal, mahogany, pine.
Common wood for toys (softest).—Alder, beech (small), birch (small), sallow, willow.
Best woods for Tunbridge ware.—Holly, horse chestnut, sycamore (white woods); apple-tree, pear-tree, plum-tree (brown woods).
Hardest English woods.—Beech (large), box, elm, oak, walnut.
Common furniture and inside works.—Beech, birch, cedars, cherry-tree, deal, pines.
Best furniture.—Amboyna, black ebony, cherry-tree, Coromandel, mahogany, maple, oak (various kinds), rose-wood, satin-wood, sandal-wood, sweet chestnut, sweet cedar, tulip-wood, walnut, zebra-wood.
Foreign hard woods, several of which are only used for ornamentalturnery.—
Nos. 3, 8, 16, 33, and 34 are frequently scarce.
Nos. 3, 5, 8, 9, 10 are generally close, hard, even tinted, and the more proper for eccentric turning, but others may also be employed.
Nos. 4, 5, 10, 12, 14, 17, 18, 19, 30, 32 are generally abundant and extensively used. All the woods may be used for plain turning.
Elasticity.—Ash, hazel, hickory, lance-wood, sweet chestnut (small), snake-wood, yew.
Inelasticity and toughness.—Beech, elm, lignum vitæ, oak, walnut.
Even grain, proper for carving.—Lime-tree, pear-tree, pine.
Durability in dry works.—Cedar, oak, poplar, sweet chestnut, yellow deal.
Colouring matter(red dyes).—Brazil, braziletto, cam-wood, log-wood Nicaragua, red sanders, sapan-wood.
Colouring matter(green dye).—Green ebony.
Colouring matter(yellow dyes).—Fustic, zantes.
Scent.—Camphor wood, cedar, rose-wood, sandal-wood, satin-wood, sassafras.
Indiarubber,manufactured into sheets, with or without canvas insertion of single, double, or treble thickness, up to 36″ wide and to1⁄2″ thick; cord to 1″ diameter; tubes, plain, or with canvas insertion or wire coiled inside or outside, from1⁄4″ to 4″ bore, usually in 30′ and 60′ lengths. Washers, rings, rollers, strips, belts, and moulded articles of every form.
Guttaperchais manufactured into similar articles.
Leather.Most of the varieties are manufactured from the skins of oxen, sheep, goats, deer, horses, dogs, hogs, and seals, and the larger skins are divided into butts, shoulders, cheeks, and bellies, the dimensions depending of course upon the size of the animals. Ox hides are the largest and kid skins the smallest in general use.
For mechanical purposes ox hide, raw or tanned, is chiefly used, as for valves, seatings, belts, piston leathers, &c. Sheep skins can be obtained either strained, half-strained, or unstrained; the first are hard and comparatively stiff, the last-named soft and pliable as cloth. Other soft varieties are goats’ skins and chamois leather. There are many imitations of leather, but they are rarely employed in mechanical constructions.
Vulcanised fibreis often used for similar purposes to leather, as for valves, seatings, joints, &c. It is made in two varieties, medium and hard, and in sheets up to 1″ thick.
Ebonite.A hard, black, horny substance, moulded into any required shape.
Papier mâché.Solid paper, moulded from pulp into any required form.
Asbestos,in sheets, cord, packing of various sections, loose fibre, millboard, &c.
Ivory,from tusks and teeth.
Bone.
Vegetable ivory;nuts about the size of eggs.
Packings for glands, &c., are made of cotton, hemp, and other fibres, asbestos, indiarubber, &c., in round, square, and other sections.
For general purposes this comprises Furnaces, Stoves, Ranges, Ovens, Boilers (seeSection 6), Hot-blast, Steam-heated Vessels, Gas Jets, &c., most of which are tolerably well known and in common use.
For special purposes in connection with machinery various heating devices are required, of which steam and gas are those most universally used. Steam tubes or coils may be carried through any fixed or movable part of a machine. Steam-heated surfaces, such as tables, pans, chambers, &c., steam-jacketed cylinders, and similar contrivances, are much used. Gas jets from perforated tubes, which may be shaped to any required position, are also convenient for dry heat and higher temperatures than can be obtained from steam.
Hot irons are sometimes used, shaped to fit a cavity, but of course require to be replaced periodically.
Hot water in pipes or jackets, and hot air in flues are common appliances for warming and drying; with the former its circulation must be provided for, and with the latter, either a forced draught or an upward inclination given to the flues to maintain circulation.
1876. Gill pipesfor radiating the beat of steam or hot water.
1877. Gill stove,on similar principle, presents an extensive surface in contact with the air for radiation of heat.
1878. Rolls for bar iron,grooved to suit the section required, one-half the groove being usually in each roll, and the size and shape of the grooves are graduated down from that of the square billet to the finished bar.
1879. Grooved rollsfor producing a tapered bar.
1880. Rollers for turning upand welding tubes from a flat strip.
1881. Bending rollers.
1882. Rolls for solid tyres,without a weld.
1883. Wire drawing apparatus.
For grips for drawing wire, &c., see Nos.505,518. Laths of various sections are drawn through suitable steel dies by a draw bench; the end of the lath is held by a grip tongs and the lath drawn forcibly through the dies (using a lubricant) and afterwards straightened. Rolling does not answer for this kind of work.
The drawing frame used for cotton and other fibres has two, three, or more pairs of rollers; the lower rollers are grooved longitudinally and the upper ones weighted and covered with leather, the lower ones being geared together to drive at proportionate speeds, so that in passing through, the material is stretched between each pair of rollers, the object being to extend and lay all the fibres parallel.
For drawing lead pipes, seeNo. 1183. Earthenware pipes are made by a similar process.
1884. Ordinary solid swelled distance rodwith collars, used for compressive strains.
1885. Similar strut,but formed of tube with end collars screwed in.
1886. Double flat-bar cambered strut,stiffened by distance pieces and bolts.
1887,1888,1889, &1890. Sections of varieties of the foregoing.
1891. Braced strut;usually of flat bars on edge, riveted together at the intersections.
1892. Tubular swelled strut,of plate iron, used for masts, sheer legs, crane jibs, &c.
1893. Built up strut,from segmental bars.
1894. Trussed strut;the trussing is 90° apart, but may be at any angle; the central bar of course takes the actual thrust, and the truss rods keep it from bending or buckling. See alsoNos. 295to300,320.
Ties,for tensile strain only are usually of round iron, flat or other simple section, tube, or even chain, rope, or wire.
Plate 108Larger plate.
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Many varieties will be found illustrated underSection 32. The following are moderntypes:—
1895. Diagonal paddle engines,for light draught vessels. May of course be either of two or three cylinder type and either high pressure or compound.
1896. One of the most favourite types of vertical overhead cylinder screw engines,with half standards and distance rods, one, two or three cylinders, simple or compound. The condenser is usually in the back standards and the pumps behind. Simplicity and accessibility are its chief advantages.
1897. Stern wheel, side lever engines,not often required in practice. The ordinary construction of horizontal engines usually accommodates itself for stern wheel driving. SeeNos. 575to579, &c.
1898. Double standard vertical overhead cylinder screw engines,the type commonly adopted for the heavier class of vessels, and frequently made for triple expansion. It is of very rigid construction, but not quite so convenient for accessibility to the working parts asNo. 1896. The condenser and pumps are at one side, built into the standard, and the engines are handled from the opposite side or from an elevated platform.
1899. Overhead cylinder and distance rod type,the lightest and simplest form in use for small engines. Every part is easily seen and got at, and the top weight is reduced to a minimum.
1900. Is a variety ofNo. 1896,with tandem cylinders and two cranks for triple expansion.
1901. Is also a variety ofNo. 1898,with tandem cylinders for triple expansion. In this plan the intermediate stuffing box is got rid of by using two piston rods to the lower cylinder, coupled to the piston rod of the upper or high-pressure cylinder by a crosshead.
1902. Compound overhead standard engines,for twin screws.
1903. Diagonal twin screw engines.
Plate 109Larger plate.
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1904. Horizontal twin screw engines.
1905. Plan of cylindersas usually employed forNo. 1902.
1906. Oscillating paddle engines,sometimes made with cylinders at 90° apart and a single crank, asNo. 564.
1907. Overhead oscillating twin screw engines.
1908. Annular cylinder paddle engines.
1909. Overhead cylinder side-lever paddle engines.
In addition to the above some special types are occasionally employed, as the Willan’s three-cylinder plan for screw engines. SeeNo. 592, also varieties ofNo. 593, high-speed types.
The ordinary appliances for these purposes comprise hammers of all kinds and anvils or blocks of all shapes to suit the work, rammers and mallets of wood. The steam hammer being the machine almost invariably used, is too well known to need illustration. It is made with single or double standards, and though differing somewhat in details is practically the same machine wherever manufactured.
The following are apparatus employed for particular cases, and not so well known.
1910. The drop hammer,for power. The grip pulleys are put in gear by the hand lever to raise the hammer and shaft: it is sometimes worked by hand by a simple cord and pulley.
1911. Dead blow power hammer.The crescent-shaped crosshead bar has a positive motion from the crank pin, but the hammer head is attached to it by strong horizontal springs, and therefore has some little play above and below a horizontal line.
1912. The pile engine and monkey.The latter is generally raised by a hand or power winch, but a multiplying gear steam or hydraulic cylinder has been employed.
1913. Another form of dead blow power hammer,but with a straight laminated plate spring, to which the hammer head is fixed.
1914. Another type of spring power hammer.
Plate 110Larger plate.
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1915. Revolving centrifugal rapid blow hammer.
1916. The old-fashioned tilt hammer,still in use in many places, especially where water-power is employed.
For stamps, &c., seeNos. 250&271.
Besides the foregoing there is the gas hammer of Messrs. Tangye, the pneumatic hammer, and a variety of power hammers with variable stroke. SeeNo. 1606.
Instruments for the production of sound are scarcely within the province of the mechanical engineer, but of late years several of them have been employed in connection with mechanical means for producing sound—for fog signals, whistling, and other forms of sound signalling. Musical sounds are produced by vibration of air from wind, string, or reed instruments. In wind instruments the vibration is produced by the lips and modified by the shape and length of the tube. Strings are either bowed, as in the fiddle, struck, as in the piano, or fingered, as in the harp. Reeds are springs vibrated by a current of air. In the harmonium and concertina class of instruments there are no tubes or pipes added to the reeds to modify the sounds produced; but in the organ pipe the reeds have pipes added which greatly augment and qualify the sounds. Other special sound-producing instruments are illustrated here.
1917. The Siren, or steam turbine whistle,the loudest instrument known, consists of a slotted cylindrical drum revolving inside a fixed drum; the slots are angular (see plan), so that the rush of steam revolves the inner loose drum rapidly and the sound is directed by the trumpet-shaped hood. A pair of slotted discs is also sometimes used for the same purpose instead of the slotted drums.
1918. Mechanical fog-horn;ordinary bellows are often used to supply the blast.
1919. Iron gong,struck with a muffled hammer.
1920. Harmonium reeds, or free reeds;the tongue covers a slot of same size and shape, and can vibrate into and out of it, but without touching its edges; the gravity of tone or pitch depends on the size and thickness of the tongue.
1921. Organ reed pipe;the tongueAin this case beats, with a rolling contact, upon the reedB, which is tubular, closed at bottom and opening at top into the pipeC, which extends upwards from the blockD;Eis the tuning wire which regulates the vibrating or free length of the tongue.
1922&1923. Wood and metal organ pipes,which are practically large whistles, the vibration of the column of air in the pipe being produced by the wind striking the edge of the lipA.
Steam whistles are bells with a ring-shaped slit below, from which the issuing steam strikes the lower edge of the bell.
Other forms are now made giving a more musical sound, and in some cases a double note, usually an interval of a major third, asC-E, by a modified form of pipe with two lips.
Striking bells of various shapes are extensively used.
Gongs are cheese-shaped metallic hollow suspended vessels, and are struck by a muffled hammer.
Musical sounds are also produced from slips of glass, or chilled iron, glass bells and tumblers, and also from resonant magnetic iron blocks.
1924,1925,1926.SeeSec. 98.
Plate 111Larger plate.
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1927. Application of a single crosshead and boltto close two covers, as in a pump clack-box.
1928. Cone seated cover,with hand-lifting crossbar and recess.
1929. Crosshead and man- or mud-hole,as commonly used for boilers, &c.
1930. Cast-iron manhole and block;T-head bolts are generally used, but also eye-bolts, as inNo. 937.
1931. Wrought-iron plate lid,or cover for a tank.
1932. Wrought-iron dished cover,with hinged crossbar andT-screw used largely for gas retorts.
1933. Furnace door;hinged, with inside plate to protect the door from the heat.
1934. Manhole door with water seal,or packed recess to keep back gases, smell, &c.
1935. Screwed plug handhole.
1936. Wrought-iron boiler manhole cover, and block,a special manufacture.
1937. Type of sliding door;can be made airtight by planing the seatings.
Hinged doors are well-known. For hinging, seeSection 50. For fastenings, see Locking Devices,Section 49.
See alsoNos. 931,937,940,962.