It simply shows the heights between floors, etc., and really represents all that the plumber needs so far as the elevations generally given by the architect are concerned. From the elevations given by the architect, unless indeed, they are N°1 zontal nor vertical, but as some angle between, may best be described from Figs. 24 and 25. Suppose in Fig. 24 the line A B has been drawn, and it is desired to draw a second line parallel to it. To do this, place one of the triangles in the position which No. 1 has, with one of its edges matching up with the line AB. Then place another triangle No. 3 against No. 1 triangle, as shown. Now, holding triangle No. 3 firmly in place, move No. 1 along to a second position, shown by No. 2, when line C D can be drawn parallel to A B. Any number of parallel lines can be drawn in this way. It does not matter how the triangles are put together, so long as one can move along on the other. Thus in Fig. N° 3 N°2 Fig. 24 elevations of the plumbing work itself, the plumber gets no other help than the several heights which will help him in figuring his vertical lines of pipe, etc. Now, before bringing this chapter to an end, there is one bit of instruction that we should give, and it will be helpful in laying out a part of the work shown in the cellar plan. The point to which we refer, is the running of lines at an odd angle, so that they shall be parallel to each other, as for instance, either line of conductors, which run at an angle with the main line. Of course horizontally and vertically, it is not difficult to get lines parallel, for all that is necessary is to move the tee square or triangle from one position to another, at the required distance apart from the first line. The way in which the result is reached when the lines are neither hori. NO Fiq 25. 25, the two triangles are placed differently, but the lines E F and G H can be drawn parallel in just the same manner. This method of drawing parallel lines should be kept in mind, for it is the practical way of doing such work. T CHAPTER V of in representing runs of pipe This new position is shown by No. 1. After having shown such a line position, place No. 2 triangle in the posi. of pipe, it is necessary to show the hubs tion shown by No. 3, with one of its od pipe and fittings, and the lines repre- edges at right angles to the line of pipe, senting the hub are of course at right as it must of necessity be. angles to the direction of the pipe. It will be clearly seen that by sliding Referring now to Fig. 26, let us sup- No. 3 along No. 1, lines at right angles to pose the two parallel lines representing the direction of the line of pipe can be the pipe have been drawn at some odo drawn at any desired point. It has taken angle, and it is desired to put in the per. quite a few words to explain this method, pendicular lines showing the hubs. We simple as it is, and it is a good example will suppose that the lower line on the of the difficulties in carrying on a course pipe has been drawn by placing the tri- of this kind in any other way than by angles. No. 2 and No. 4 together, and oral demonstrations. An instructor could following the method explained above. explain a great deal to the pupil before Still holding No. 2 in position, draw No. hiin very quickly, whereas the writing of 4 along the edge of No. 2 into a new the same explanation demands of the one Method of Drawing Lines Perpendicular to Each Other at Right Angles. Another Method of Drawing Lines Perpendicular to Each Other at Common Angles. closely can derive much benefit from the GH will be the line desired. knowledge of the subject gained. This latter statement may often be put If two lines are to be perpendicular to to use, as we may see from Fig. 28. In each other at common angles, such as making drawings of plumbing work, it 30 deg., 45 deg. and 60 deg., the problem is far oftener the case that a branch is is simple, and may easily be seen by refer- taken from a horizontal or vertical line ence to Fig. 27. of pipe than from a line running at odd The line A B is drawn at 30 deg. with angles. A regular Y branch is always The Main Pipe Drawn With a Tee Square—Lines of Branch With 45 Degree Triangle. the horizontal, and can be obtained sim- at an angle of 45 deg. with the main line ply by drawing a line along the edge of of pipe. Therefore, in laying out work, the 30 deg. triangle placed against the tee such as shown in Fig. 28, the main pipe square. To obtain a line at right angles is drawn in with the tee square, and the to A B just reverse triangle No. 1 to the lines of the branch are drawn in with No. No 2. the use of the 45 deg. triangle in position No. 1. Lines representing the hubs are put in with the same triangle in posi. tion No. 2. In Fig. 29 we show right and wrong methods for drawing quarter and eighth bends, and in Fig. 30 like methods for running traps. We do this in order to show our readers some of the mistakes which it is natural for a beginner to make, and which he can the better avoid after comparing wrong constructions with correct. The common quar. ter bend is a compact fitting as No. 1 will show, and the mistake often mado is in giving it the long sweep shown in No. 2, although there are special fittings made after the manner of No. 2. The same fault is often found in the drawing of eighth and other bends. In drawing the quarter bend, first run the horizontal and vertical lines, then with the compasses set on a center close to the inter. section of the two inside lines, describe the curves so that they will run smooth. ly into the respective lines. Of course both curves are struck from the same center. Many times the eighth bend will be used between a Y branch and a straight run of pipe. In this case, draw in the lines for the Y branch and the straight line, then connect these lines with the proper curve. Not until this is done should the hub on the branch or on the bend be drawn. Now with reference to NO 3. NO 4. FIG. 29. Right and Wrong—Quarter and Eighth Bends. |