Abstract: An exercise rowing machine has a frame and a swing arm pivotally connected thereto which is manually pushed and pulled in opposition to an adjustable hydraulic load-resisting mechanism pivotally connected between the frame and the arm. This mechanism has a pair of spring-loaded, independently adjustable flow control valves at opposite ends for controlling flow to and from opposite ends of a cylinder which a double-acting piston reciprocates responsive to movement of the swing arm. The range of adjustment of the spring pressure on the valves is preset.

Abstract: An improved pin member adapted for use in a tubular connection where said pin member is adapted for coaxial threaded engagement with a box member having a counterbore for receiving the pin member. A pilot surface is disposed from a distal-proximate end to the distal end of the pin member inclining to a lesser extent than the angle of the incline of an internal sealing surface of the pin member. The pilot surface is substantially parallel to the axis of the connection. This pilot surface allows the end-of-pin flat thickness to be increased thereby allowing positioning of the interengaged threads so as to provide an increased radial thickness of the box member thereby increasing the axial tensile strength capability and burst pressure rating of said tubular connection while additionally protecting said internal surface of said pin member and providing a rugged end-of-pin flat.