BT - DRILL CHUCK ARBOR Taper SizeBT-30, 40 and 50 A ➚ A .00020 AT3 Taper 58-60 HRc Ra 4µin L L1 K D G Designation K L L1 D G BT30 DC J2X1.187 J2 1.187 .215 1.181 M12 BT30 DC J3X1.187 J3 1.187 - - M12 BT30 DC J6X1.187 J6 1.187 - - M12 BT40 DC J2X1.750 J2 1.750 .589 1.181 M16 BT40 DC J3X1.750 J3 1.750 .477 1.339 M16 BT40 DC J33X1.750 J33 1.750 .598 1.181 M16 BT40 DC J4X1.750 J4 1.750 .539 1.732 M16 BT40 DC J6X1.750 J6 1.750 .589 1.181 M16 BT50 DC J2X1.750 J2 1.750 - - M24 BT50 DC J3X1.750 J3 1.750 .157 1.339 M24 BT50 DC J33X1.750 J33 1.750 - - M24 BT50 DC J4X1.750 J4 1.750 .157 1.339 M24 BT50 DC J5X1.750 J5 1.750 - - M24 BT50 DC J6X1.750 J6 1.750 1.54 1.339 M24 811