Wrench Circle

Two large wrenches were used to connect and disconnect the drilling tools.  This was accomplished with a perforated wrench circle plate fastened flat to the derrick floor and the use of a wrench bar.  The plate had two rows of staggered holes into which the point of the wrench bar could drop.  The wrenches have a square recess which fitted exactly around the square of the  tool at the joint.  The wrenches could be moved by pushing  the wrench bar, sometimes assisted by also pushing a horizontal wooden lever against the bar.  This operation was variously called "making up the joints", "tightening and loosening the screw joints", and "setting up joints".  It is illustrated in the figure below.

This type of tool joint wrench was commonly used on the derrick floor until 1900.  After Redwood, 1913.

The circle plate was replaced around 1890-1900 by the Barrett patent oil well jack which was a much more convenient device.  It used a notched circle track with a jack which could move forward or in reverse by the strokes of the lever.  The jack manipulated the wrench.  The Barrett type oil well jack is illustrated below.

After 1900 the Barrett type oil well jack with its notched steel track, travelling socket lever with wood handle (operating lever) and wrench post (shown at right end of circle) became the principal apparatus for wrenching and unwrenching oil well tools.  It was built with single and double action, weight 190-200 lbs.  One model was called the "Duff Genuine Barrett Oil Well Jack".  From Bacon and Hammer, 1916.

National Supply Company listed a heavy duty Barrett wrench jack with a Titan track in their catalog no. 30, 1921. Details are shown in this illustration.

The above cut of a taper joint is taken from "Everything for Oil Wells", a 1913 catalog of Oil Well Supply Co.

This circle track and wrench are in working position, the wrench still in place below the collar of a drilling tool.  The lower tools are still in the old hole.  The operators did not need a board floor on which to operate the circle jack.  In this case they simply set up on the ground.  A very old portable drilling machine stands a foot or two outside the picture at the right.  A misshapen sapling is growing over the circle at the left.