Abstract: A vertical orientation column capable of orienting or positioning a large workpiece, such as a marine propeller, with respect to four or five axes and a process for machining large and complex workpieces. The column is so constructed as to allow quick installation and removal of the workpiece and to position the workpiece in close proximity to the particular tool which is operating on the workpiece. The orientation column of the present invention is advantageously employed in the machining of propeller blade surfaces and the column is compatible with automatically controlled tools, such as machine tools operated by numerical control. In addition, the orientation column itself may be operated by numerical control. A process for rigidly mounting and moving a large workpiece to be machined for machining of complex shapes therefrom.