Features TIME SAVING: These woodworking mortises can reduce the labor strength of construction workers, speed up construction, and reduce construction costs in the building, installation, renovation, and decoration industries. MULTIPLE SPECIFICATIONS: Users can use different specifications of square hole drill bits with the right power of square hole machine to make the square holes that meet the requirements. HIGH SPEED STEEL: These square hole bits are made of high speed steel and are heat treated for a high hardness bit and incisive square chisel for long life. EASY TO USE: This drill can be used with a mortising machine to double the effect. Square holes need to be made with a drill, hammer or other tools. PRIMARY USE: Our square hole bits are ideal for drilling square holes in wood using a mortising machine or mortising attachment. Specification: Item Type: Woodworking Square Drill Bits Set Material: HSS Punch Size: 6.4mm (1/4in) 8.0mm (5/16in) 9.5mm (3/8in) 12.7mm (1/2in) Package List: 4 x Woodworking Square Drill Bit 4 x Storage Box Package List 4 x Woodworking Square Drill Bit 4 x Storage Box