BLACK 1-1/4″ ADAPTOR TO 5/8″ CORING BIT FOR CONCRETE CORE DRILLS. This is a brand new adapter for concrete coring drills. It adapts 1-1/4″ 7UNC threads used by most concrete core drills to 5/8″ 11 which some coring bits take. This allows you to use 5/8″ thread bits with a coring drill. This is a great adapter to use BLUEROCK 5/8″ DRY type coring bits with. Drill and Dry type bit pictured is not included although they are for sale. This is a center hole type adapter and can be used for both wet and dry type drilling.