This table is arranged so as to show comparative prices of different grades of pipe. The prices for standard pipe being the net prices resulting from the discount and list prices given in table 2, for plain pipe. The prices here given will fully answer the purpose of estimate. Exact prices can only be had by correspondence with the manufacturers, who will quote the latest lists and discounts. That feature of the pipe which is of the greatest consern to the well driller is the thread and it is chiefly on account of the thread that heavier pipe is needed. If the pipe is thin and light so much of the body of the metal is cut away in the operation of threading as to leave a thin shell not sufficiently strong to withstand the driving blows without danger of stripping the thread. If the pipe is heavy the body of metal back of the threads is stronger and the pipe therefore more able to withstand heavy work. COUPLINGS. (See table No. 7.) The common form of coupling is straight threaded, that is, the line of the threads is parallel to the outer surface of the coupling. An improved form gives greater strength to both pipe and coupling and distributes the strain more evenly over the line of the thread. This is known as the patent TAPER COUPLING. From the illustrations of this form of compling, shown in connection with the advertisements on the front and back covers and by Fig. 2 on page 20.. it will be seen that the inner face, or threaded surface of the coupling, has the form of a funnel to fit a corresponding conical taper on the pipe. In drive-pipe the ends of the pipe meet at the middle of the coupling. As made by the Oil Well Supply Co., Pittsburg, Penn.-See advertisement Fig. 2 shows sections of pipe joints and the patent taper coupling referred to on P. 18. Fig. 2. 13.00 10.00 14 12.00 14.00 11.15 13.00 14 17.00 13 00 14 17.00 16.15 II 20.00 24.00 II PATENT SLEEVE COUPLING. FLUSH JOINT. INSERTED JOINT. wwww Drive pipe is of standard weight and size but more expensive, stronger and better on account of its being made of a better quality of iron. Then, too, the threads are cut longer to fit a longer and stronger coupling (see table 7) and of sufficient length to permit the ends of the pipe to butt together when coupled-this it not the case in standard pipe---thus very greatly adding to the strength of the pipe in the operation of heavy driving, the pipe being practically continous and not separated at each joint. This is the distinguishing feature of drive pipe. Size-outside diameter, weights-pounds per foot. |