A stretch-forming machine of the type wherein a pair of opposed curving jaw assemblies grip opposite end edge portions of a metal sheet for initially stretching the metal sheet into a yield state, and forming the metal sheet into a predetermined curved configuration, characterized in that each jaw assembly comprises: a) a jaw (24, 25) comprising an array of adjacent grippers (50, 52) moveable relative to each other to collectively define the curve of the jaw (24, 25) configured to grip opposite end edge portions of the sheet from adjacent a first corner to adjacent a second corner of the sheet; b) a moveable yoke (12, 13) connected to the jaw (24, 25); c) a pivot assembly (32, 33, 34, 35) connecting the yoke (12, 13) to a beam way (15, 16) for pivoting the jaw (24, 25) about a lateral, horizontal pivot axis defined by a point located within at least one center gripper and a plane defined by the at least one center gripper and at least two grippers (50, 52) gripping opposite end edge portions of the sheet, the pivot assembly (32, 33, 34, 35) being aligned with the lateral, horizontal pivot axis at the point within sheet-gripping openings defined by the at least two grippers (50, 52) gripping opposite end edge portions of the sheet, such that the at least one center gripper can pivot about the point of the pivot axis during pivotal movement of the at least one center gripper thereby maintaining the point in essentially the same position during pivoting; and d) at least one actuator for pivoting the jaw (24, 25) about the pivot axis and urging grippers adjacent the at least one center gripper in a stretching direction to further progressively stretch the first and second corners of the metal sheet while minimizing further elongation along a centerline of the metal sheet proximate the at least one center gripper. a) a jaw (24, 25) comprising an array of adjacent grippers (50, 52) moveable relative to each other to collectively define the curve of the jaw (24, 25) configured to grip opposite end edge portions of the sheet from adjacent a first corner to adjacent a second corner of the sheet; b) a moveable yoke (12, 13) connected to the jaw (24, 25); c) a pivot assembly (32, 33, 34, 35) connecting the yoke (12, 13) to a beam way (15, 16) for pivoting the jaw (24, 25) about a lateral, horizontal pivot axis defined by a point located within at least one center gripper and a plane defined by the at least one center gripper and at least two grippers (50, 52) gripping opposite end edge portions of the sheet, the pivot assembly (32, 33, 34, 35) being aligned with the lateral, horizontal pivot axis at the point within sheet-gripping openings defined by the at least two grippers (50, 52) gripping opposite end edge portions of the sheet, such that the at least one center gripper can pivot about the point of the pivot axis during pivotal movement of the at least one center gripper thereby maintaining the point in essentially the same position during pivoting; and d) at least one actuator for pivoting the jaw (24, 25) about the pivot axis and urging grippers adjacent the at least one center gripper in a stretching direction to further progressively stretch the first and second corners of the metal sheet while minimizing further elongation along a centerline of the metal sheet proximate the at least one center gripper.