Commercial cast metal Tee's are not made for use of the A.O.D. Tuyere. A cast metal Tee is made for pipes going in the opposite directions. The A.O.D. Tuyere has a inner oxygen tube and outer cooling gas tube. Misalignment of the threads in a cast Tee can cause the Inner Copper Production Tube to be misaligned and even damaged at the orifice of the tuyere. This misalignment reduces and prevents critical cooling gas from flowing evenly through the Tuyere