F1 type boring heads 1.Min graduation:0.001,0.0005,0.01mm 2.Dia of boring:3/8"-5",1/2"-9" etc 3.Max offset:5/8",1",1-5/8" etc F1 type boring heads1.Min graduation:0.001,0.0005,0.01mm2.Dia of boring:3/8"-5",1/2"-9" etc3.Max offset:5/8",1",1-5/8" etcmodel no.DHMax offsetBoring bar DiaMin graduationDia of boringF1-1/250 61.6 5/8" 1/2" 0.001" 3/8"-5" F1-3/475 80.2 1" 3/4" 0.0005" 1/2"-9" F1-1100 93.2 ...