External helix tube for installing screw-type earth anchor

An apparatus particularly useful for installing screw-type anchors in the earth, including a separable flight and an anchor bolt of any desired length which may be assembled at a job site. A tubular mandrel is provided for applying torque to the anchor near its flight for rotating the same into the ground; a flight is also rigidly affixed to the mandrel near its foot so that it may, in turn, be rotated out of the ground after an anchor is installed. A mobile frame is provided which may be moved to a side where an anchor is to be installed, said frame being adapted to transfer torque from a portable torque unit to the earth. Pivotal outriggers are provided at the base of the mobile frame so that torque reaction loads may be more widely distributed to the ground. The shape of the flights on the anchor and mandrel are preferably helical, so that the flight will cut through the soil instead of churning or forcing the same upward (as is the case with conventional augers).