The coil-style threads produced by these taps are shallower and more widely spaced than standard thread sizes. Use them for quick threading action with compatible fasteners. They’re made of high-speed steel and are for use on most metal and plastic. The square shank is compatible with tap wrenches and tap holders for drill presses and milling machines. All have a plug chamfer with 3-5 chamfered cutting threads, so they're suitable for start-to-finish tapping. When using them to tap closed-end holes, be sure to leave sufficient space at the bottom for chips to accumulate.