Method of forming a universal joint

A method of making a universal joint, comprising the following steps:

• forming a tube of high-strength low-alloy steel;
• forming a plurality of pairs of coaxially aligned holes through the unexpanded tube at spaced predetermined locations along the longitudinal axis of the tube;
• cutting the tube along a curvilinear cutting path around the holes forming a pair of projecting arms each arm including one of the coaxially aligned holes and U-shaped recesses between the arms, thereby forming a plurality of universal joint yokes;
• cutting the tube perpendicular to the longitudinal axis of the tube between pairs of coaxially aligned holes to form the open ends of the tube;
• pivotally interconnecting the universal joint yokes with cross shafts each having a rod received into one of the coaxially aligned holes, the projecting arms each extending into one of the U-shaped recesses forming a universal joint;
• and
• folding over the open end of the tube along the longitudinal axis thereof, doubling the thickness of the tube at the open end to increase the torsional strength of the universal joint.