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Flat due to oval tubing?

Posted: Tue Nov 11, 2014 4:34 am
by P@rick
Hi all,
My Besson 993 is overall flat. I’m about to cut the main tuning slide, but I noticed that the tubing right after the main tuning slide is oval shaped. That part of the tubing has an S-curve and exactly around that area its oval shaped. It could be a production error or it could be induced by excessive force while it was used, but it should not be oval. I checked other Besson 993 Tubas and they are not oval in that area.
Could oval tubing be the cause of the tuba being flat?
Thanks!

Re: Flat due to oval tubing?

Posted: Tue Nov 11, 2014 9:13 am
by Dan Schultz
I doubt it unless it's REALLY flattened. It's not unusual for a tube to be flattened a slight bit in bent areas. Crooks are seldom perfectly round. But... you'll never know for sure unless you fix it.

Re: Flat due to oval tubing?

Posted: Tue Nov 11, 2014 10:52 am
by P@rick
TubaTinker wrote:I doubt it unless it's REALLY flattened. It's not unusual for a tube to be flattened a slight bit in bent areas. Crooks are seldom perfectly round. But... you'll never know for sure unless you fix it.
It's not REALLY flattened, but the other two Bessons which I compared were perfectly round :(
Thanks!

Re: Flat due to oval tubing?

Posted: Tue Nov 11, 2014 11:19 am
by imperialbari
So now it is a matter of cleaning the interior and then having the right balls?

Re: Flat due to oval tubing?

Posted: Tue Nov 11, 2014 3:17 pm
by tusabtuba
No, cut the slide. Tusabtuba

Re: Flat due to oval tubing?

Posted: Thu Nov 13, 2014 10:45 am
by P@rick
bloke wrote:Conn 20J tubas have oval tubing in their pistons...yet there seems to be a consensus that a "tuning bit" inserted between the receiver and the mouthpiece is recommended.

bloke "if-then"
...so...oval tubing makes a Tuba sharp...so...you are saying I need to make more tubing oval to make my Tuba less flat? :mrgreen: :wink:

Re: Flat due to oval tubing?

Posted: Thu Nov 13, 2014 11:18 am
by Dan Schultz
P@rick wrote:
bloke wrote:Conn 20J tubas have oval tubing in their pistons...yet there seems to be a consensus that a "tuning bit" inserted between the receiver and the mouthpiece is recommended.

bloke "if-then"
...so...oval tubing makes a Tuba sharp...so...you are saying I need to make more tubing oval to make my Tuba less flat? :mrgreen: :wink:
:D. The tuning bit is more to overcome ergonomic issues.

Re: Flat due to oval tubing?

Posted: Thu Nov 13, 2014 11:20 am
by imperialbari
Wasn’t a tuning bit calculated into the design of the 2XJ series? Purpose being flexible ergonomics.