Corbett Portable Drilling Rig

George Corbett in 1884, using equivalents of the major equipment of a standard carpenter's rig, fitted these devices into a portable (skid-type) rig that had the facilities of a spudder and driller.  Corbett's inventions and his 1888 patent (of his 1884 rig) were acquired by the Oil Well Supply Co. of Pittsburgh and Oil City, Pennsylvania.  Perhaps alterations were made.  In any case, the portable machines were marketed in at least three models of the skid-type but they could also be mounted on wheels.

The Corbett rig could be built with a regular walking beam (as in the drawing) or with a segment walking beam.  The rig shown, having only a 600 foot depth capability, would be usable only in very shallow oil territory, like the flats bordering Oil Creek, and probably wouldn't reach the oil-bearing beds if the drill site was on the high flanks of the valley.  Other Corbett models could drill deeper.  Illustration from 1904 Oil Well Supply catalog.

Being quite compact, any Corbett rig could be mounted on wheels if the buyer so preferred.  The pictured model made by Oil Well Supply Co. is rigged for temper screw drilling, has a segment walking beam with center irons and has a hinged mast and double pulleys.  A segment walking beam is short and stubby.  Illustration from 1904 Oil Well Supply catalog.