Зображення сторінки
PDF
ePub
[blocks in formation]

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

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.

[blocks in formation]

T

CHAPTER V

HIS method would be made use

of in representing runs of pipe at oblique angles with the main. After having shown such a line of pipe, it is necessary to show the hubs on pipe and fittings, and the lines representing the hub are of course at right angles to the direction of the pipe.

[blocks in formation]

position away from the line just drawn. This new position is shown by No. 1.

Now holding No. 1 firmly in its new position, place No. 2 triangle in the position shown by No. 3, with one of its edges at right angles to the line of pipe, as it must of necessity be.

It will be clearly seen that by sliding No. 3 along No. 1, lines at right angles to the direction of the line of pipe can be drawn at any desired point. It has taken quite a few words to explain this method, simple as it is, and it is a good example of the difficulties in carrying on a course of this kind in any other way than by oral demonstrations. An instructor could explain a great deal to the pupil before him very quickly, whereas the writing of the same explanation demands of the one

[graphic][subsumed][ocr errors][subsumed]

Method of Drawing Lines Perpendicular to Each Other at Right Angles.

[merged small][merged small][merged small][merged small][merged small][merged small][ocr errors][merged small][merged small][merged small]

Another Method of Drawing Lines Perpendicular to Each Other at Common Angles.

closely can derive much benefit from the knowledge of the subject gained.

If two lines are to be perpendicular to each other at common angles, such as 30 deg., 45 deg. and 60 deg., the problem is simple, and may easily be seen by reference to Fig. 27.

The line AB is drawn at 30 deg. with

GH will be the line desired.

This latter statement may often be put to use, as we may see from Fig. 28. In making drawings of plumbing work, it is far oftener the case that a branch is taken from a horizontal or vertical line of pipe than from a line running at odd angles. A regular Y branch is always

[ocr errors][merged small][merged small]

The Main Pipe Drawn With a Tee Square-Lines of Branch With 45 Degree Triangle.

the horizontal, and can be obtained simply by drawing a line along the edge of the 30 deg. triangle placed against the tee square. To obtain a line at right angles to A B just reverse triangle No. 1 to the

at an angle of 45 deg. with the main line of pipe. Therefore, in laying out work, such as shown in Fig. 28, the main pipe is drawn in with the tee square, and the lines of the branch are drawn in with

the use of the 45 deg. triangle in position No. 1. Lines representing the hubs are put in with the same triangle in position 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 quarter bend is a compact fitting as No. 1 will show, and the mistake often maa 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 intersection of the two inside lines, describe the curves so that they will run smoothly 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 1.

N° 2.

No 3.

N° 4.

FIG. 29.

Right and Wrong-Quarter and Eighth Bends.

[graphic][ocr errors][subsumed][subsumed][subsumed][merged small]
[graphic][subsumed][subsumed]

Model for Students to Work Out-Combinations of Pipe and Fittings as we give it. This should be drawn on same scale, at least no smaller.

« НазадПродовжити »