. The railroad and engineering journal . be parallel to each other, but asin fig. 161, the lines at the root and those at the point will notbe exactly parallel, as the learner will observe if he lays downall the dimensions of the thread precisely.* In doing ihis he will have found out how veiy difficult it is todraw a thread of this kind with sufficient precision, so that itwill not appear more or less distorted, and if he should allenipt10 do it on a reduced scale, or to draw a smaller sized boll, hewill find lhat the difficulty increases with the reduction in thescale and size of the boll. F
. The railroad and engineering journal . be parallel to each other, but asin fig. 161, the lines at the root and those at the point will notbe exactly parallel, as the learner will observe if he lays downall the dimensions of the thread precisely.* In doing ihis he will have found out how veiy difficult it is todraw a thread of this kind with sufficient precision, so that itwill not appear more or less distorted, and if he should allenipt10 do it on a reduced scale, or to draw a smaller sized boll, hewill find lhat the difficulty increases with the reduction in thescale and size of the boll. For this reason an easier method isusually empoycd in practice, which saves much time, labor andpains, and for most practical purposes answers as well as thatwhich has been described. A bolt is drawn as in fig. 165. * The fii c lines «/, .^A, and */^, in figs. i6i and 162 .end at i, ?, 3in , are intended to represent pencil lines, and should be rubbed out after thedrawing is completed. Vol. LXIV, No. ENGINEERING JOURNAL. 469. b h Fig. 161. 2-INCH SCREW: FULL SIZE, 2-INCH SCREW AND NUT: FULL SIZE.
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectrailroa, bookyear1887
