When extended reach is necessary Rotabroach offer extension arbors of various lengths. For use when the face of the hole to be cut is lower than the surface on which the machine is standing. Extension arbors are manufactured with 3/4" (19.05mm) shank fittings which are accepted in almost all magnetic drill stands. This arbor is 50mm long x 33.5mm (Approx.) Diameter and comes with allen key and two pilot pins to suit.