Master bushings are designed for sq and pin drive Kelly bushings from sizes 17 1/2” to 37 1/2” rotary tables. The pin drive allows the use of extended insert bowls to meet flush with the top of table which means better slip support and preventing damage to drill pipe. The sq drive bushing has a 4” deep recess to be used with the sq drive Kelly bushings. Short and medium style are used in the sq drive for shallower depth and drilling. 

The 37-1/2” MPCH is a pin drive hinged master bushing specially designed for floating and semi-submersible drilling operations. With insert bowl No.3 and optional insert bowls No.1 and No.2, the MPCH will handle 2-3/8” to 13-3/8” OD drill collars, tubing and casing. Unit come complete with No.3 insert bowl, bit breaker adapter plate and lifting sling.