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Threading mouthpieces for screw rims
Posted: Wed Apr 19, 2017 3:02 pm
by ttf_Doug Elliott
There are potential unforeseen issues when threading other mouthpieces for my screw rims...
I'm working on one now, and I've seen this before:
What appears to be a one-piece mouthpiece isn't one piece - the rim has been pressed on.
I think this particular one will come out OK, but it might not.
This is from one of the well known manufacturers.
Another one I've seen: It's a bit if a surprise to start cutting into a mouthpiece and find that it's nickel-silver, not brass.
Threading mouthpieces for screw rims
Posted: Wed Apr 19, 2017 3:20 pm
by ttf_TromboneMonkey
I suppose those are cost-saving measures? A company can make hundreds of cups and press on the different rims?
Seems legit...
Threading mouthpieces for screw rims
Posted: Wed Apr 19, 2017 3:51 pm
by ttf_BGuttman
I have a couple of very old mouthpieces (~100 years old) that have pressed rims. One is not completely pressed on and has a sharp corner in it that I can feel. I don't use them much since I only have two horns that use them (neither of which I play much) and I have other two part mouthpieces that are properly aligned.
Making a rim and pressing it on a mouthpiece saves material over carving it from a solid cylinder.
Doug, is it much different to machine nickel silver versus 342 brass? (342 has a little lead in it and that makes machining easier. Most of the mouthpieces I have tested were that form of brass. Another reason to make sure the plating is intact.)
Threading mouthpieces for screw rims
Posted: Wed Apr 19, 2017 4:03 pm
by ttf_Doug Elliott
I'm just mentioning it because I don't want to be responsible for ruining a mouthpiece that I couldn't have known would be a problem.
Nickel silver cuts a little differently from brass.
Standard brass rod is currently 360, not 342
Threading mouthpieces for screw rims
Posted: Wed Apr 19, 2017 4:31 pm
by ttf_BGuttman
With the RoHS requirements, 342 would no longer be allowed in anything that touches your mouth.
I didn't test any mouthpieces that were post-RoHS. Now I can't because I'm no longer employed at that lab.
Threading mouthpieces for screw rims
Posted: Wed Apr 19, 2017 5:46 pm
by ttf_Doug Elliott
360 has lead in it too
Threading mouthpieces for screw rims
Posted: Wed Apr 19, 2017 5:46 pm
by ttf_Doug Elliott
360 has lead in it too