In order to design a system intelligently the engineer should have some knowledge of the methods of actual construction, the tools used, etc. It is customary where a piece of work is to be done to send a supply of pipe and fittings to the building somewhat greater than is required, and the workman after receiving the plans of construction, which show the location and sizes of the various pipes to be erected, makes his own measurements, cuts the pipes to the proper length at the building, threads them and screws them into place.

Steam Fitting 1000195

Fig. 41.

The tools belonging to this trade consist of tongs or wrenches for screwing the pipe together, cutters for cutting, taps and dies for threading the pipe, and vises for holding it in position while cutting or threading. A great variety of tongs and wrenches are to be found on the market. For rapid work no tool is superior to the plain tongs (shown in Fig. 40), especially for the smaller sizes of pipes. The alligator wrench (shown in Fig. 41) is used in a similar manner on light work and where the pipes turn easily.

Steam Fitting 1000196

Fig. 42.

Steam Fitting 1000197

Fig. 43.

For large pipe, chain tongs of some pattern are the best, and may be used with little danger of crushing the pipe. (See Fig. 42.) A form of wrench, known as the Stilson, one form of which is shown in Fig. 43, is widely used. The wrenches or tongs which are used for turning the pipe, in most cases, exert more or less lateral pressure, and if too great strength is applied at the handles there is a tendency to split the pipe. The cutter ordinarily employed for small pipe consists of one or more sharp-edged steel wheels, which are held in an adjustable frame (see Fig. 44); the cutting being performed by applying pressure and revolving it around the pipe. A section of one of the cutting wheels is shown in Fig. 45. With this tool the cutting is accomplished by simply crowding the metal to one side, and hence burrs of considerable size will be formed on the outside and inside of the pipe. Usually the outside burr must be removed by filing before the pipe can be threaded. The inside burr forms a great obstruction to the flow of steam or water, and should in every case be removed by the use of the reamer. There are many forms of reamers for use in various cases; one of the simplest is shown in Fig. 46.

Steam Fitting 1000198

Fig. 44.

Steam Fitting 1000199

Fig. 45.

Steam Fitting 1000200

Fig. 47.

Steam Fitting 1000201

Fig. 46.

The ratchet drill is another tool often used, and is especially useful in drilling holes in pipes or fittings after the work is in place. One of these is shown in Fig. 47. A common form of vise used for holding the pipe while cutting and threading is shown in Fig. 48. The combination vise is shown in Fig. 49. The dies for threading the pipes are usually of a solid form, each die fitting into a stock or holder with handles. (See Fig. 50.) The cutting edges of the dies should be kept very sharp and clean, otherwise perfect threads cannot be cut. In cutting threads on wrought iron pipe, oil should always be used, which will tend to prevent heating and crumbling, and make the work easier. In erecting pipe great care should be taken to preserve the proper pitch and alignment, and to appear well the pipes should be screwed together until no threads are in sight. Every joint should be screwed from 6 to 8 complete turns for sizes 2 inches and under and from 8 to 12 turns for the larger sizes, otherwise there will be danger of leakage.

Steam Fitting 1000202

Fig. 48.

Steam Fitting 1000203

Fig. 49.

In screwing pipes together, red or white lead is often used.

It will generally be found that linseed or some good lubricating oil will be equally valuable. If possible, the work should be arranged so that it can be made up with right and left couplings or other fittings.

Steam Fitting 1000204

Fig. 50.

Packed joints, especially unions, are objectionable and likely to leak after use. Flange-unions with copper gaskets should be used on heavy work. Good workmanship in pipe-fitting is shown by the perfection with which small details are executed, and poor workmanship in any of the particulars mentioned may defeat the perfect operation of the best designed plant.

Standard Bath Tub for Hospital Use.

Standard Bath Tub for Hospital Use.