The old fashioned rule of thumb was if using cables, use a plastic bell crank, or use solid wire in a plastic bell crank. If using a metal bell crank, it would cut the cable pretty quickly, as was seen on early ARF Noblers, and they need to be bushed with a brass bushing, or, again, use solid wire for lead outs. These days, I am like the others here and use the small tubing, brass or copper, as it covers all the bases. With tubing that small, a simple candle will get hot enough to heat it to a red color for annealing.. or a gas stove burner.
Type at you later,
Dan McEntee