This is where it gets interesting. The original Magnus runners were 2"OD tubing, but the best match to the stock ports was ~1.65"OD tubing. I needed to make some nice transition funnels and the last thing I wanted to do was slice a tube lengthwise and form them myself. So, I lathed a steel bar into a tapered mandrel, annealed the tubes, went to the hydraulic press, and to my surprise everything worked like it was supposed to, which is seldom the case... Pressing out the mandrel after pressing it into the tube was exciting - it almost maxes out the 20-ton press and once it finally lets go you better have something underneath to catch it, it's pretty much a small explosion, lol. By the way, to anneal aluminum you just scribble some sharpie lines on the tubing, heat it up until the marks disappear, and then let it slowly cool down. The thermometer on my grill hood maxes out at 700°F and that's about the time the marks burned off. I am sure the temperature at the grates is much higher.