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This eBook from the Gutenberg Project consists of approximately 112 pages of information about Scientific American Supplement, No. 315, January 14, 1882.
at A D B, Fig. 44, put on some resin, and with a well-heated copper-bit drop some solder roughly on the point from B to A, then draw the bit over it again to float the solder, being especially careful not to let the joint open when coming off at A. Some plumbers think fit to begin here, but that is a matter of no importance.  Do not forget that if your joint is not properly prepared, that is to say, true and even, it is sure to be a failure, and will have a “higgledy-piggledy” appearance.  Some difference of opinion exists as to the best method of making these joints:  one workman will make a good joint by drawing it while, on the other hand, another one will do it equally well by wiping it.  Drawing will be fully explained in a part on pipe making.  It may, however, be here mentioned that it is a method of making the joint by floating the solder along the joint with the ladle and plumbing-iron.

[Illustration:  FIG. 45.]

It is not uncommon for plumbers to make their bends with only one joint on the back.

PULLING UP BENDS.

In London, it is the favorite plan to make bends without cutting them.  Fig. 46.  It is done by taking a length of pipe, and, just where you require the bend, lay it (with the seam at the side) upon a pillow, made by tightly filling a sack with sand, wood shavings, or sawdust; have some shavings ready to hand and a good lath, also a short length of mandrel about 3 ft. long and about 1/2 in. smaller than the pipe, and a dummy as shown at A B, Fig. 56.  Now, all being ready, put a few burning shavings into the throat of the bend, just to get heat enough to make it fizz, which you can judge by spitting on it.  When this heat is acquired withdraw the fire, and let the laborer quickly place the end of the mandrel into the pipe, and pull the pipe up while you place a sack or anything else convenient across the throat of the bend, then pull the pipe up a little, just sufficient to dent it across the throat.  Now, with a hot dummy, dummy out the dent, until it is round like the other part of the pipe.  Keep at this until your bend is made, occasionally turning the pipe or its side and giving it a sharp blow on the side with the soft or hornbeam dresser; this is when the sides run out as in Fig. 37.  Never strike the back part of the bend from inside with the dummy, but work the lead from the throat to the back with a view to thickening the back.

[Illustration:  FIG. 46.]

SET-OFFS.

A set-off is nothing more than a double bend, as shown at Fig. 47, and made in much the same manner.  D is the long end of the pipe.  Always make this bend first and pull it up quite square, as it will be found to go a little back when pulling up the other bend; if you can make the two together so much the better, as you can then work the stuff from the throat of one bend into the back of the other.  The different shaped dummies are also here shown:  F a round-nosed dummy, G a double bent dummy, H a single bent, I straight, J hand-dummy, ABN a long bent dummy shown at Fig. 38.

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