The Rig.-The rig ie composed of a derrick, band-wheel, bull-wheel, sand-pump reel, sampson post, walking-beam, and engine-house. The present derrick is built "balloon-frame," 16-20 ft. sq.
at the base, and 60-72 ft. high, resting on hewn oak sills 12 by 18 in., framed and pinned at the corners ; the four corner-posts are of pine plank 10 by 2 in., spiked together at right angles, and connected with cross-ties and diagonal braces of 8 by 1} in. ; the top holds the usual cast-iron derrick-pulley, and a ladder to reach it is constructed upon one side.
Tha bull-wheal now in use has four main arms of oak, 8 by 2i in., passing clear through the shaft, and locked and keyed ; the false arms between, 6 by 2 in., wedge upon each at the shaft, and are firmly held by the three thicknesses of pine boards forming the outer rim, The total length of oak shaft is 10i--12 ft., its diameter 13 in., its length between wheels 6-7 ft., diameter of wheels 6i-7 ft., and bearing-pin on ends 21- by 4 in.
The brake is a simple iron strap applied under the bull-wheel ; a wooden pawl is made to fall from above, against the arms, as a permanent stop, when desired.
The band-wheel is built of inch pine lumber, surfaced to a uniform thickness, the present diameter being about 7 ft. ; the rope-pulley on one side is 5 ft., and the face of the wheel 9 in. The grooves of the rope-pulleys on both band- and bull-wheels are made of hard wood, and, to ensure a perfect outer circle, the edges are turned off after the wheels are firmly mounted on the shaft and revolved on temporary bearings.
The sand-pump reel has always been the most awkward part of a well-rig ; acting as a friction pulley against the band-wheel with the bevelled face necessitated by the different angle of the shaft, its tendency was to self-destruction, even when most carefully and securely fitted up. A solid wheal of hard wood with wooden keys is sometimes used ; also a piece of casing as a shaft, with a cast iron pulley keyed upon it. The best reel is an oak shaft, about 8 ft. in length, 8 in. in diameter, with arms of the wheel passing through the shaft and enclosed with an iron rim.
The sampson-post and walking-beam have gradually increased in size, until the one is a post 20 in. sq., and the other 24-26 ft. in length, with a section at the centro of 30 by 18 in. The great weight of the walking-beam has, perhaps, some of the effect of a fly-wheel, where a fly-wheel never theless is not found to be a practical success. The utmost care is needed in making the foundation
of the sampson-post and band-wheel frame perfectly solid and substantial ; two long hewn sills for the latter, not less than 12 by 20 in. in section, pass clear under the derrick-sills ; the jack-posts, cap, and braces of the band-wheel frame, being of pine 10 by 12 in., the cap bolted through to the sill.
The Well.—Col. Drake's invention of the driving-pipe affords the best means of passing through soft overlying earth to the rock. Tha pipe used at present is 8 in. in diameter, of 1-in. cast-iron, driven down into the earth in sections of 8 ft. in length, connected with wrought-iron bands, heated and shrunk on. Putting down a thin iron pipe of 6 in. diameter below the lowest fresh-water vein, and retaining the surface-water by a water-packer between the outside of the pipe and the wall of the well, enables the driller to proceed without annoyance from this source, and, when the well is completed, to take his tubing out of the well at pleasure, still keeping the water permanently from the oil-bearing rock. In fact, the entire operation of drilling and pumping is carried on through the casing, and not until a well is finally abandoned is the casing withdrawn.
The modern water-packer is a great improvement on the bag of flaxseed formerly used ; the weight of the column of water presses the leather against the sides of the well, forming an effectual stopper. By means of a left-banded thread, it can be loosened in a few minutes, and drawn out of the well without difficulty.
Drilling-Tools.—A sat of drilling-tools, as used to-day, weighs 1800-2600 lb., and costs about 70/. It consists of a temper-screw, rope-socket, auger-stem, sinker-bar and substitute, the jars, two bitts, a round reamer, a fiat reamer, and two wrenches. The temper-screw varies little from that in former use, except in size, the present length being about 5 ft. The auger-stem, sinker-bar, and substitute are respectively 21,14, and 5 ft. in length, the last being used in starting a well. They are made in the body, of common round iron (2i-3 in.), with boxes and pins of Norway iron. Pins are 2/ in. in length, in. in diameter, 8 threads to the in., and with the least possible taper, to prevent being loosened by the constant jar, which also has a tendency to crystallize the iron in the pins and boxes, making it necessary to renew them at intervals.