Re: Re: How close is close enough?


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Posted by John Swensen on October 18, 2000 at 14:15:54:

In Reply to: Re: How close is close enough? posted by Joe encouraging S. on October 17, 2000 at 22:30:16:

Joe, first of all, thank you for your reponse. I must not have been getting my question across very clearly, so I'll try again.

As far as I know, all soft-soldered tube joints are reinforced with an external ferrule, the internal diameter of which is often at least ten thousandths larger than the outside diameter of the tubes at the joint. During the soldering operation, tin and lead fill the gap, but the tubes can move around so they don't meet exactly (I have witnessed quite noticeable misalignments (>.005") in the visible joints on some very expensive and prestigious tubas). Imperfect joints that are visible can be seen and fixed pretty easily, at the cost of some burned lacquer or messed-up silver on a finished horn. The internal joints are much harder to inspect without using some pretty sophisticated (and expensive) fiber optics or miniature video cameras.

My question, directed to those who have messed around with this stuff more than me, is how much of a misalignment can be tolerated with little or no impact on the tone quality, intonation, or response? Is it worth coming up with an internal alignment jig (say, titanium, spring loaded, with a means of retrieving it after soldering a joint)? Or are these kinds of misalignments inconsequential, relative to the ends of slides (chamfered or not)?


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