Quick-check reference gauges are reference tools used to check the sizes and tolerances of parts. These gauges offer a reliable and simple method for checking a size, thread, or angle. Center gauges, also called fishtail gauges, are used for hand-grinding threading tool bits and for setting tools perpendicular to workpieces. Drill point angle gauges are used to sharpen drill bits and check that they have the correct angle. Radius gauges, also known as fillet gauges, are used to measure the concave and convex radius or fillet of metal objects. Thread pitch gauges measure the thread width of various threaded tools. Wire and sheet metal thickness gauges are circular metal discs with holes and slots cut into them used as a reference to check sizes. Tap, drill, and screw checker gauges are sheets of steel with holes that correspond to sizes and are used to confirm a cutting tool’s size. Thread measuring wires measure the thread pitch diameter of threaded parts or taps.