Unibit Hole-Enlarging Step Drills

• UNIBIT Step Drills have an exclusive single radial concave flute
• This design allows the drilling of perfectly round holes in thin materials quickly and with less effort
• Each bit is constructed of industrial grade high speed molybdenum steel,and is heat treated to a hardness of between 61 and 63 on the Rockwell scale
• This assures maximum strength and long life
• Shank size: 1/2"
• Step thick: 1/8"