26 with each adjacent column 61 b 61 c and 61 d moving progressively further away from the drill string 26 a plurality of stops 63 a 63 e are included on the pipe transfer mechanism 24 the stops 63 a 63 e are arranged in a horizontal and vertical offset from one another e g arranged in a pattern resembling a u201c stair step u201d those of skill in the art will appreciate that other patterns and physical locations relative to one another may be used for the stops the transfer mechanism 24 includes rod pocket 60 at a first end of the mechanism and a rod blocking member 64 extending from the rod pocket 60 to the second end of the mechanism it will be appreciated however that the rod blocking member 64 may be arranged and configured to other lengths in order to provide the function of blocking drill pipe 28 from exiting non selected columns of the magazine 22 on the lower side of the mechanism is a gear rack 66 which is engaged by a driven gear 68 movement of the driven gear 68 moves the transfer mechanism 64 back and forth under the magazine and transversely relative to the longitudinal axis of the drill string 26 by driven what is meant is that the gear is powered in a manner by which the gear rotates with enough force to move the transfer mechanism a hydraulic fluid motor not shown may be used to drive the gear 68 with the hydraulic fluid.