Fig. 122. Diagram of Carnegie 86-Foot Structural Steel Rotary Derrick. The Carnegie Steel Co. makes this derrick in five sizes, 59 feet, 72 feet, 80 feet, 86 feet and 106 feet in height. Refer to pages 375-377 for safe working loads for derricks. Fig 123. Side elevation and ground plan of 106-foot Texas rotary drilling rig, showing machinery installed ready for drilling. PUMP SIDD Fig. 124. Side elevation and ground plan of 106-foot California rotary drilling rig with extra wind braces, showing machinery installed ready for drilling. ELEVATION RIG The rig for rotary drilling consists of a derrick and the necessary rotary machinery, no bull wheels and walking beam being required. The sand reel is not used for there is no means of operating it. The sand line is spooled on the draw works drum, sometimes being wound over the casing or drilling line. A steel crown block is usually used. Erecting the derrick, refer to Fig. 121. If the ground where the derrick is to be built is not level the pump side should face toward the downward slope to secure the advantage of the drainage for the slush trench, see Fig. 156. The derrick corners, consisting of two courses of 2 x 12-inch boards, eight feet in length, are first laid. Half way between each corner four pieces of 2 x 12-inch boards three feet in length are spaced one foot apart. The corner sills D, and the short side sills are placed on these 2 x 12-inch footings. Next the casing sills and derrick side sills are put in place. The engine mud sills are set so the ends will abut against the side sill, the engine pony sills are placed on the mud sills, and the engine block mounted on them. The engine block and sills are framed and keyed as shown in Fig. 149. In placing the side sills a margin of two and one quarter inches should be left between the end of one sill and the sill on which it rests at each corner to provide a shoulder or base for the end of the leg timbers. Description of the erection of a standard derrick on page 47 will answer also for the rotary derrick. The derrick floor sills are next placed and the derrick floor and engine walk are laid. Some rotary derricks are built with the floor extended four feet, so the pumps can be installed outside the derrick. When this is done, the two derrick side sills should be four feet longer, see Fig. 123. One or more platforms must be provided in the upper part of the derrick on which the man who handles the elevators, when pulling out or running in drill pipe, may stand. The 112-foot derrick usually has two platforms, consisting of three 2-inch planks extending across the derrick on the side opposite the |