Top Hammer Rock Drilling Tools PDF Download: Top Hammer Drilling Tools Bench Drilling R32 Bench Drilling T38 Bench Drilling T45 Bench Drilling T51 Coupling Components Semi-Bridge Coupling Small non threaded central bridge Most suited to high torque machines Full-Bridge Coupling Used for surface applications Maintains tighter joins Better uncoupling characteristics Best suited to machines with independent rotation Adaptor Coupling Useful when there is a need to change from one thread size or type to another Typically used in special circumstances