. Railway mechanical engineer . inst thestraight edge, scribe this same dimension on the outsideof each front main jaw intersecting the line B at D andprick-punch the intersection. Scribe a line E F on the engine frames above the jaws,and parallel with the top of the frames. Then scribe the ,257 258 RAILWAY MECHANICAL ENGINEER Vol. 91. No. 5 line G H through the prick-punch mark D the full lengthof the jaw and perpendicular to the line E F. To drawthis line perpendicular to E F, take a pair of short tramsset to a distance greater than from D to the line EF, andwith P as a center, scribe arcs c
. Railway mechanical engineer . inst thestraight edge, scribe this same dimension on the outsideof each front main jaw intersecting the line B at D andprick-punch the intersection. Scribe a line E F on the engine frames above the jaws,and parallel with the top of the frames. Then scribe the ,257 258 RAILWAY MECHANICAL ENGINEER Vol. 91. No. 5 line G H through the prick-punch mark D the full lengthof the jaw and perpendicular to the line E F. To drawthis line perpendicular to E F, take a pair of short tramsset to a distance greater than from D to the line EF, andwith P as a center, scribe arcs crossing the line EF. Withthe dividers, find a point on the line EF midway betweenthese arcs, and draw the perpendicular line through thispoint and D. After doing this on both sides of the engine, find thecenter of the main pedestal jaws. As tlie main-rods are(or at least should be) kept to standard length, a very goodmethod of locating the main jaw centers would be to makethe jaw centers a standard distance from the face of the. Fig. 3 cylinders. However, if the jaws have not become wornenough to recjuire much filing or milling, scribe a line acrossEF true with the face of the front jaw, and from the point/, its intersection with the line EF, lay off on the line EF,a distance equal to one-half the standard width of the drivingbox, plus the standard thickness of the shoe. Prick-punchthis center, which is L. .other method to be used when the jaws are worn, is tolocate the jaw centers midway between the points / and point K is obtained by scribing perpendicular to theline EF from a point on the face of the back jaw threeinches from the top of the jaw. Whichever method is
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectrailroadengineering
