BORING BARS Inscribed Circleof Insert (inch).156 .187 .219 .250 .313 .375 .500 .625 .750 1.000 1.2 1.5 1.8 2 2.5 3 4 5 6 3 4 5 6 8 1.2 1.5 2 3 4 5 1.2 1.5 2 2.5 3 4 5 6 2 3 4 5 1.5 2 3 4 E . Insert Size L C R 2 v Boring Bar Style m Insert Relief Angle , Hand F J K L Symbol Relief Angle Figure Hand Symbol -1° -3° 15° -5°(91°)(93°)(75°)(95°) A Right R B End Cutting Side Cutting End Cutting Side & End Cutting C Left L P Q U X D -27.5° -17.5° -3° (117.5°) (107.5°) (93°) E Neutral N F End Cutting End Cutting End Cutting Back Boring G N P O Other E005