Laying out for boiler makers and sheet metal workers; a practical treatise on the layout of boilers, stacks, tanks, pipes, elbows, and miscellaneous sheet metal work . pon where great accuracy is required, as the sides ofthe square are too short to determine the direction of a longline. The method of squaring up lines by a geometricalconstruction will be explained later. All measurements alongstraight lines are made with an ordinary 2-foot rule or steeltape. For measuring along curved lines, the tape may beused by holding it to the curve at short intervals, but a betterdevice is the measuring
Laying out for boiler makers and sheet metal workers; a practical treatise on the layout of boilers, stacks, tanks, pipes, elbows, and miscellaneous sheet metal work . pon where great accuracy is required, as the sides ofthe square are too short to determine the direction of a longline. The method of squaring up lines by a geometricalconstruction will be explained later. All measurements alongstraight lines are made with an ordinary 2-foot rule or steeltape. For measuring along curved lines, the tape may beused by holding it to the curve at short intervals, but a betterdevice is the measuring wheel, as shown in the illustration. at the point on the wheel indicating the fractional part of arevolution remaining. The use of these tools, as well as the construction of theordinary geometrical problems, will be apparent from theproblems in laying out which are to be taken up and fully Also such rules as can be given for the allowancesto be made due to bending, flanging, etc., will be explained inconnection with these layouts. In general, there are four kinds of surfaces which must bedealt with in boiler work, and of which the layer out must be. FIG. 4.—PLAN AND ELEVATION. This wheel is made of a thin piece of metal, beveled to asharp edge, and having a circumference of a certain exactlength, as 2 or 3 feet, with the divisions in inches and frac-tions of an inch marked upon it. The wheel is pivoted to ahandle and can be run over the line, measuring its lengthexactly. If it is impossible to get one of these graduatedwheels, a blank wheel of any diameter may be used by firstrunning it over a straight line on which the distance to belayed off has been marked, and noting the number of com-plete revolutions of the wheel and placing a mark upon it atthe fractional part of a turn left over. Then the wheel canbe run over the cur\ed line until it has made the same num-ber of complete revolutions and the end of the curve marked able to find the development. These are p
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License: Licensed
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Keywords: ., bookcentury1900, bookdecade1900, bookidl, booksubjectsteamboilers
