A knot/hinged drill bit is a drill bit that can be used for drilling through or making countersinks. It leaves a very smooth and neat mark. The tip of the bit is very short, which allows for making almost flat-bottomed countersinks. The knot drill bit gets its name from its traditional use: drilling out knots from pieces, but today it is also used for all other purposes. For drilling through or making countersinks Hardened steel Sizes: 15, 25 and 35 mm In a wooden storage case