Back Home / Fasteners / Threaded Inserts / HELICALLY COILED INSERT UNC 5/16″-18 HELICALLY COILED INSERT UNC 5/16″-18 SKU: HCI56C Categories: Fasteners, Threaded Inserts Made of stainless steel wire that has been rolled to a carefully controlled thread form. When installed, inserts adjust to a tapped hole, becoming a functional thread with a strength exceeding the original. Designed to repair stripped threads in a variety of metals, aluminum, aluminum alloys, steel and cast iron. Thread size:5/16″-18 Drill size: 21/64 Case Quantity: 10 Log In For Pricing