Manufactured from selected steel these boring bars are accurately machined. Bars incorporate broached holes that accept standard high speed steel or carbide toolbits conveniently. Bars are supplied with an allen-key but without toolbits. Boring Bar Length: 6-3/4 inch (171mm) Boring Bar Diameter: 9/16 inch (14.28mm) Holder Length: 3 inch (76mm) Square Size: 3/4 inch (19mm) Tool Bit Size: 1/4 inch