OFU 2005-3 SHACSHAC OFU 2005 3 Double Ball Nut, 20 mm, 5 mm Lead, Class 3 Preload The SHAC OFU 2005 3 double ball nut is a 20 mm, 5 mm lead nut with class 3 preload for compact CNC and automation axes that demand high accuracy and stiffness. Its preloaded twin nut construction keeps backlash very low, giving stable positioning and good surface finish on light and medium duty machines. SHAC is manufactured in China but engineered to compete with Taiwanese linear