Posted by Dave on September 07, 2002 at 00:13:46:
I'm looking for someone who has tried different methods to build up a rotor before machining it on a lathe and who can offer some advice based on experience. I've been thinking of adding a layer of silver solder to the rotor, but I wonder, would regular solder work ok? Since the body of the rotor doesn't touch the valve casing, what difference would it make, other than electrolytic? Yes, I know that plating is one
way to go, but since I have some brass-colored silver solder I thought it might be an
acceptable alternative.
I've already machined the valve shafts, built up the bearings by silver-soldering new
brass bushings in place, and remachined the bearings, and the rotor is centered within
a couple of thousandths of an inch, but it has about 10 thousandths clearance due to
many years of neglect.
The tuba is about 100 years old, more of a wall-hanger than a playable instrument, especially with the bad leak on the fourth valve. Valves 1,2 and 3 still have acceptable compression.