The V-Coil thread inserts are manufactured from precision profiled, high quality, austenitic, chromium nickel, stainless steel wound into a helical spiral. The V-Coil inserts have a spring like appearance and once fitted their position is maintained by the action of radial pressure between their coils and the flanks of the tapped hole. This pressure exists because the free diameter is larger, by a calculated amount, than the installed diameter. Their unique design ensures that once installed using either manual or automatic tools they provide strong permanent internal threads resistant to both heat and corrosion. Each inserts length is 1.5x its diameter