Abstract: The method makes it possible, in the context of the industrial-scale production of control valves, to reduce the spread on the torque of the valve law P=f(C) which spread is due to machining inaccuracies and other variations in geometric parameters. This method consists, for each control valve produced, in adapting the stiffness of the torsion bar and/or of the connection between this bar and the spool of the control valve, according to the difference between the valve law measured for this valve and the theoretical law for the type of valve concerned. In particular, adaptation can be achieved by selecting the axial position of the pin that connects the torsion bar and the spool so as to modify the torsion length of this bar.

Abstract: A fitting is mounted on a hydraulic cylinder tube having a cylindrical outer surface by first positioning the fitting against the surface of the tube with the fitting engaging the surface along an arcuate contact line and then directing a laser beam at the contact line and moving the laser beam along the contact line to weld the fitting to the tube. The surface is centered on an axis and the fitting is positioned such that the contact line is at most 120.degree. long relative to the axis.