-HeliCoil is a Thread Insert used for creating stronger internal threads in soft metals and also for repairing damaged or stripped internal threads by regaining the original size. HeliCoil Inserts provide positive means for protecting and strengthening all tapped threads. HeliCoil protects tapped threads against wear and damage in all metals and other materials. HeliCoil Inserts develop maximum clamping load and bolt tension through efficient use of applied torque. HeliCoil Thread Repair Kits.