Each power transformer is custom designed to succeed in the environment they are placed in. Our design philosophy requires elimination of sharp edges on all insulating parts (wood structures, spacers, rings, etc.) and tolerances on winding coil dimensions to be measured in millimeters. Our stringent process requires customized insulating parts, achieved using the 5-axis milling machine. Onsrud’s 5-axis machine is used to manufacture internal wood supports, structures, and insulation components. The machine is computer-controlled for accuracy, and can manufacture directly from AutoCAD, Inventor, and Master Cam 3-dimensional drawings. We also use a 3-axis milling machine for other insulation components.