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the intention of the writer to 13, 14 and 15, give correct illustra-
at first, and growing more diffi tional incorrect sketches showing ercult as the subject advances. Those who rors that are often made. Now as to layare following the series with the idea of ing out the work in Fig. 13, simply reusing the instruction given as a means member that the horizontal lines are to of learning how to make plumbing be made with the tee square as shown drawings, should lay out the work in Chapter I, and the vertical lines by given, endeavoring to make it as nearly using the triangle against the tee square. like the model which we show as pos We would say that in working out these
Fig. 13- Horizontal Lines to be made with T square
Fig. 14-Showing Correct and Incorrect Sketch
In laying out the Y, Fig. 14, notice that the branch is at 45 degrees with the length of the fitting, and consequently should be laid out with the 45 degree
exercises they should be done in pencil, and not inked, as that will be taken up later on. Since no inking is to be done, all lines should be made plain and not shaded with heavy lines as our sketches are made.
The shading is done to give character to an illustration and to set it out, and the method of doing it will be taken up under the subject of inking. In laying out the tee in Fig. 13, be careful to proportion the branch properly. Do not get it into the center of the fitting as the incorrect sketch shows, and do not have the branch loo long, as is also shown. Another point, a small one however, is the
Fig. 16 -Curve in Lower Sketch Not Properly Drawn
triangle placed against the tee square.
Do not place the branch far down on the fitting as the incorrect sketch shows.
The hubs shown on the latter sketch do not give as good an appearance to the work as those in which a bead is shown at the top. Although the intersection of the branch and fitting is a curve, as shown, the method in the incorrect sketch answers as well, and is much easier. In drawing the strap, Fig. 15, draw in the straight parts of the trap first, and put in the curves next. Do not get the three branches of the trap too far apart, as shown in the incorrect sketches, and the middle part should the center to either of the lines, the curve neither be quite vertical, nor on too much of a slant. Speaking of the curves reminds us that a little instruction is needed on the proper manner of putting
Fig. 15 - Another Example of Correct and Incorrect
Work intersection of the branch with the main part of the fitting. Do not make it in the form of a curve as the incorrect sketch shows, but with two 45 degree lines.
them in. If two lines at right angles to each other are to be joined by a curve, it is necessary to take the center for the curve at an equal distance from each
With the center taken at any point on this line, the two straight lines can be joined with a smooth curve, the curve being longer or shorter as the center is taken further from or nearer to the angle.
We are often required to put in curves joining lines which are at some odd angle as in Fig. 17. In this case it is more difficult to find a line of centers, and it is usual to keep trying one point after an. other until the right point for the center is found. In fact, draughtsmen seldom take the trouble to find a line for their center as Fig. 16 shows, but soon become so expert in finding by trial the right location from which to strike the curve, that they seldom need more than a couple attempts before obtaining the right point.
We have stated that our intention is to
Fig. 17-Showing How Curves are Put In, Joining
Lines at Odd Angles line, and from this point, with a distance
the compasses equal to that from will join both lines as the upper sketch in Fig. 16 shows.
A very common error in those just beginning the subject is to draw the curve as it appears in the lower sketch of Fig. 16, that is, so that it does not run smoothly into the straight lines, but leaves a corner at the point where the curve joins. Even though the center is taken so that it is equally distant from each line, this fault may occur by taking too long a radius on the compasses, a distance greater than the perpendicular distance from the center of the line.
The exact point for taking this center is on the 45-degree line from the angle made by the two lines, the dotted line in the sketch as illustrated on page 17.
Fig. 18—Sketch Obtained by Looking Down Into
the Sink give exercises for practice work. In addition to that we shall carry along the general subject of plumbing drawing as well.
There are two views which are neces.
Figure 19—Showing an Elevation of a Common Kitchen Sink location of fixtures and soil, waste and These two drawings, if desired, may be vent lines, leaving the plumber to put in taken as exercises. his connections according to his own The suggestions made concerning the ideas.
five preceding sketches should be applied However, on many of the best jobs in drawing up Fig. 19. It can easily be nowadays, architects are giving an eleva seen that each of these views is equally tion, showing the manner in which the necessary to the complete representation work is to be laid out.
of the sink and its connections. Fig. 18
shows the location of the sink more fully chan Fig. 19, but Fig. 19 shows the connections more fully-the connection under the floor into the stack for instance, the height at which the sink is set, etc.
As we said in looking into the matter of projection as the fundamental principle of drawing, the plan (Fig. 18) is obtained by looking down onto the sink, and the elevation (Fig. 19) by looking directly at it, just as one would look at the front of a building.
This elevation is taken looking at the front of the sink as the arrow points. An elevation might as properly have been taken looking at the end of the sink, as the dotted arrow points. There are certain reasons, however, why the elevation which we show gives a better view than the other. If the elevation had been taken from the end of the sink, it will
be noticed that the waste and vent lines would have come one in front of the other instead of side by side as the front elevation shows, and the trap and its back air pipe would not have shown broadside to us, as Fig. 19 reprezents.
Therefore, in this work, the layout of the work should be sized up first, and such an elevation chosen as will show the work to best advantage. There is another point to be observed from Figs. 18 and 19.
When drawn on the same scale as these two views are, and should be when possible, similar measurements taken on each should agree with each other. For instance, measure from the end of the lower drip board in the plan to the center of the vent line, and take the same measurement on the elevation. The two measurements will be found to be the