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CABLE-TOOL DRILLING

Colonel Drake and Uncle Billy used a steam-powered cable-
tool rig to drill the Oil Creek site. Early drillers in California and other
parts of the world also used cable-tool rigs. To understand the
principle of cable-tool drilling, picture a child's seesaw. Put a child on
each end of it and let them rock it up and down. This rocking motion
demonstrates the principle of cable-tool drilling. To explore it further,
take the kids off the seesaw and go to one end of it. Tie a cable to the
end and let the cable dangle straight down to the ground. Next, attach
a heavy chisel with a sharp point to the dangling end of the cable.
Adjust the cable's length so that when you hold the end of the seesaw
all the way up, the chisel point hangs a short distance above the
ground. Finally, let go of the seesaw. Releasing the seesaw lets the
heavy chisel hit hard enough to punch a hole in the ground. Pick up
the seesaw and repeat the process. Repeated rocking of the seesaw
makes the chisel drill a hole. The process is quite effective. A heavy,
sharp-pointed chisel can force its way through a great deal of rock
with every blow.
A cable-tool rig worked much like a seesaw. Of course, cable-
tool rigs had more parts and, instead of a seesaw, a cable tool had a
powered walking beam mounted in a derrick. At Drake's rig, a 6-
horsepower (4.5-watt) steamboat engine powered the walking beam.
The walking beam was a wooden bar that rocked up and down on a
central pivot, much like a seesaw. The derrick provided a space to
raise the cable and pull the long drilling tools out of the hole. As the
beam rocked up it raised the cable and attached chisel, or bit. Then,
when the walking beam rocked down, heavy weights, sinker bars,
above the bit provided weight to ram it into the ground. The bit
punched its way into the rock. Repeated lifting and dropping made the
bit drill. Special equipment played out the cable as the hole deepened.
Cable-tool drilling worked very well in the hard-rock
formations such as those in eastern U.S., the Midwest, and California.

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