Buffet English Horn Day 5 - 2/17/14

Today was a busy day between work and rehearsal, so I only had about a half hour between the two to work on the english horn. But 30 minutes is more than enough time to get caught in a quagmire. I'm pretty efficient at that.

I was doing the last of the swedging that I didn't complete yesterday on the Eb lever. It goes on the C# lever hinge rod, between the two ends of the C# lever. It's a key that gets used a lot, and has force exerted on it at kind of a weird angle, so it was severely worn and needed a lot of swedging. Like, more than I've ever needed to do on a key. You can see on this end how much of a gap there is between the tube and rod.

So I was doing working on that and things were going alright, but I failed to take one factor into account: As metal is worked, it hardens. So as I was swedging, repeatedly squishing and deforming the metal of the hinge tube, the metal was getting less and less flexible, until finally it couldn't absorb the stress being placed on it. That caused the end of the tube to crack in two places. This is something I should have foreseen, but thankfully all is not lost.

To fix my mistake, I first cleaned out the cracks with a fine jeweler's saw, then filled them both with silver solder. In this picture you can see that the left side of the hinge tube looks a little weird. That's the end that cracked, and the slightly darker color is the silver solder that pooled on the outside of the key.





In this next picture, you can see the end of the tube where it split. I didn't bother making the end of the tube look perfect, because that area is going to get cut off when the tube gets shortened in a few steps.

The next step was to file away the excess solder and sand the outside of the tube to restore a smooth finish and remove the distortion from the excess silver solder. It's difficult to see the color in this picture, but filing and sanding also removed the silver plating and exposed the base metal of the key - on this instrument the keys are made of brass. I'll need to buff and spot plate it later to fix that.

Next I needed to ream out the inside of the tube, which got a little bit of solder in it. That's not necessarily a bad thing, since now I can ream it just to the diameter I need so it will fit snugly on the hinge rod, thereby creating a new bearing surface in the tube out of silver solder.

Finally I shortened the tube a bit, since all that swedging made it a good bit longer, and it was no longer fitting between the two sections of the C# lever. This is when any of that nastiness at the end of the tube got removed.

Here's the whole assembly put back together. The Eb lever fits perfectly between the two halves of the C# lever, and fits snugly on the rod. Once it's spot plated, there should be no permanent damage.