Another old cornet on my bench...
You might be able to see that the valve guide for piston #1 is incorrect. Any suggestions for sources, other than waiting until parts (or a parts horn) show up on eBay? Since it's sheet metal, I'm hoping that getting someone to fab one is at least an option.
Only paid $100 for the complete horn (case, HP/LP slides, mouthpiece, mute, lyre, quick change mechanism... EVERYTHING), so I have a little room to pay for repairs.