AccusizeTools - 3'' Boring Head, 0350-0003 Good quality, excellent performance and practical design at an affordable price Maximum rigidity is assured when boring bar holder is used in an offset position Hardened and ground adjusting screw along with our wide base design guarantees long life and trouble-free use Size: 3", Hole Size: 3/4", Offset: 3/4", Thread Mount: 1-1/2~18