. The railroad and engineering journal . es are2j- in. diameter and 12 ft. lo^ in. long. The main frames are 4 in. wide and 3J in. deep. Thedriving-wheel tires are 3 in. thick, and the second and thirdpair are plain, without llanges. The driving axles are ofsteel, the journals being 7J in. diameter and 8i in. driving-box brasses are of phosphor-bronze. Theside-rods are of steel, with solid ends, provided with phos-phor-bronze bushes. The two-wheel truck has 30-in. steel-tired wheels ; thetruck axle has journals 52 in. diameter and 10 in. long. The cylinders, as already noted, are 20 x
. The railroad and engineering journal . es are2j- in. diameter and 12 ft. lo^ in. long. The main frames are 4 in. wide and 3J in. deep. Thedriving-wheel tires are 3 in. thick, and the second and thirdpair are plain, without llanges. The driving axles are ofsteel, the journals being 7J in. diameter and 8i in. driving-box brasses are of phosphor-bronze. Theside-rods are of steel, with solid ends, provided with phos-phor-bronze bushes. The two-wheel truck has 30-in. steel-tired wheels ; thetruck axle has journals 52 in. diameter and 10 in. long. The cylinders, as already noted, are 20 x 24 in. Theyare provided wiih the Richardson-Allen balanced valves ;the valve motion is of the ordinary shifting link type. Space prevents the publication of the specifications infull. These engines are excellent examples of the latestpractice, and ought to do good service. The tendertank holds 3,3oogals. The tender has brakeson both trucks, and tlie engine is also provided withdriver-brakes. Vol. LXIV, No. 10.] ENGINEERING JOURNAL. 467. 468 THE RAILROAD AND [October, 1890. THE ESSENTIALS OF MECHANICAL DRAWING By M. N. Fokney. (Copyright, 1890, by M. N. Forney.) iContinutd from page 422.) CHAPTER VI. SCREW THREADS. No description of an ordinary screw and nut is needed, ex-cepting to point out thai the threads of screws are of dififtrentforms and proportions, and that nearly all those which are com-monly used have what are called ri^lahatiHeit l/itc-ads, thatis, the threads wind around the bolt, so that when looking atthe end of a bolt the nut must be turned in the same directionthat the hands of clocks or watches turn, to screw it on, and itmust be turned the reverse way to unscrew it. The thread ofwhat are called left-hiimied screws wind around the bolts in thereverse direction to those which are right handtd, and conse-quently the nuts must be turned in an opposite direction inscrewing them on and off their bolts. For the present onlyright-handed screws will be considered. In
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectrailroa, bookyear1887
