Is there a way or an adapter to connect 1/2 O.D. tubing to a 3/8 in shut off valve? I am installing an old style clawfoot tub and the supply tubing that came with the tub is 1/2 O.D. The local plumbng supply houses say there is no way to connect this and no adapters are available but they sell the 1/2 O.D tubing. Any ideas??