Micro 100 MBB-0 Boring Bar Sets; Shank Diameter (Inch): 1/8 in; 1/8; Minimum Bore Diameter - Smallest Bar (Decimal Inch): .0180 in; Minimum Bore Diameter - Smallest Bar (Inch): .0180; Minimum Bore Diameter - Largest Bar (Decimal Inch): 0.0405 in; Min