Specialized bit for a drill designed for making a perfectly round hole in some metal material, especially stainless steel.Backer, cutting edge and cap work together to provide faster, longer-lasting cutting action.Positive rake teeth clear chips better for longer life and easier cutting.Teeth stay sharp and make smoother cuts.Used with electric drill use, which are not included here. Attention: The Hinge Boring Bit is used on bench drill or drill machine. Hand drill or electric drill is not recommended.