Engineering Wonders of the World
Volume I

ENGINEERING IN THE WORLD'S OIL FIELDS. 327 First of all a wooden derrick or square open-work tower, some 64 to 72 feet high, is erected. At one side of this the drilling gear or “ rig ” is built, which de- rives its motion from an engine whose boiler is usually placed Having finished “ rigging up,” Boring Apparatus. from 50 to 150 feet has been attained. Work is then stopped temporarily whilst the cable is attached through an intermediary, adjustable “ temper screw ” to th© “ i This latter is a stout piece of walking-beam. ’ ’ : timber 26 feet close at hand. drilling is started by the driller uncoiling some of the cable off the “ bull wheel shaft,” and passing the loose end over a pulley at the top of the derrick. The tools are then at- tached to this and allowed to hang freely within a few inches of the ground. These tools consist of a heavy blunt steel bit or chisel about 5 feet long, and of the same width as the hole which it is required to drill, sinker. 3j to 5 inches in diameter, and feet long. Next are the “ jars,” consisting of two massive flat links, which have about inches play. A small stem sometimes follows the jars, and then comes the rope socket. These sundry tools are screwed hard into each other in such will not in the knotted while the other end is coiled round the “ bull wheel shaft.” Above this comes the “ stem ” or This is made of the best round iron, to 45 come well, into a way that they apart and be lost The cable is the rope socket, Socket 25 ^Drilling' Lining Well SKETCH OF A DERRICK AND DRILLING RIG. On the right is a complete series of tools used in drilling. Drilling *Cable Walking Beam uger Stem A quick up-and-down motion is imparted to the cable and tools by means of a rope connected at one end to the crank of a shaft which is belt-driven from the engine, while the other end passes through a noose on the drilling cable, and is attached to the derrick floor. As the tools fall, their weight causes the cable to stretch, and upon the sudden reversal of the motion of the latter the tools strike a sharp blow or kick. The quick xe- petition of these blows pulverizes the ground, and a hole is made. As the hole deepens, more and more cable is uncoiled, until a depth of long, pivoted at the centre, and resting on a rigid upright support. An oscillating or see- saw motion is imparted to the other end of the beam through a connecting-rod worked off the crank and shaft referred to above. The necessary connections having been made, drilling is again proceeded with, and as the hole deepens the temper screw is let out so as to feed more cable. Drilling off the walking- beam relieves the derrick of the heavy strain of the “ kick ” of the tools. The avowed object of drilling being to pulverize the ground and reduce it to mud,