Roller Kelly Drive Bushing The roller Kelly bushings designed to match with API master bushing for driving the Kelly Suitable for hex type Kelly and Square type Kelly The drive section designed in pin type and square shoulder, strictly match API rotary table The rollers specially heat-treated for extending Kelly’s service time, replaced easily Conforming to API Spec 7K Product Specifications For Roller Kelly Drive Bushing Model Type Drive Type Fitting Kelly Size Square (in) Hexagonal (in) HDS Heavy Square 2 1/2 - 6 3 - 6 27-HDP Pin 3 - 6 20-HDP RTM4 Medium Square 2 1/2 - 5 1/4 3 - 4 1/4 20-MDP Pin 2 1/2 - 4 1/4 17-MDP
