TromboneChat

I’ve recently acquired a Bach Corp 42G where the bell seam is misaligned to the bell engraving and mounting brace. The seam is slightly skewed to the left of the brace instead, Is this something vintage Bach trombones are known for? I’ve never seen a Bach bell with a misaligned seam.

Thanks,

It was made on a Friday.

not entirely sure what you mean and some pics might help with what you are talking about.

but I have a 9" NY50 and the seam does not line up with the brace diamond points. slightly to the left side.

not sure if that helped with the discussion or not.

I don't imagine the alignment of centering to the brace diamond points makes a difference in how it sounds. Might make a difference in how bad someone's OCD gets triggered though!

I mean, I would assume that the roll stamp is put on before the bell is mounted? And then the model number afterwards? I guess it wasn't quite lined up, but I have seen other instruments where the bell brazing seem is not directly under the brace fittings.

If you like how it plays, I'm not sure it really matters.

You should see my Minick bass bell. Super crooked bell seam. I think it adds to the mojo.

mrdeacon wrote: Tue Jul 21, 2026 10:41 pm You should see my Minick bass bell. Super crooked bell seam. I think it adds to the mojo.

Don't forget older tubas with a Y-seam.

My OCD got triggered!

NotSkilledHere wrote: Tue Jul 21, 2026 6:59 pm . Might make a difference in how bad someone's OCD gets triggered though!

CDO please. Alphabetical order is preferred.

Wait until you decide to read up on the Bach Trumpet seams…. They moved the orientation of the seams on those horns at some point and you get some fun opinions there.

I have a couple that were pretty crooked, and have seen some that are almost 45 degrees off. At no point have I thought that it was a critical factor in how the horn responded, but I haven’t tested it much, either.

Cheers,
Andy

tbonesullivan wrote: Wed Jul 22, 2026 8:19 am Don't forget older tubas with a Y-seam.

I have a Conn valve trombone with a Y seam.
With the insert I guess it stretches the sheet metal a lot less and requires fewer steps to make. I wonder why they stopped doing it that way. Appearance?

Doug Elliott wrote: Wed Jul 22, 2026 6:04 pmI have a Conn valve trombone with a Y seam.
With the insert I guess it stretches the sheet metal a lot less and requires fewer steps to make. I wonder why they stopped doing it that way. Appearance?

I have always wondered that. I assumed for Tuba bells it was either to save material, or because they simply couldn't get sheet brass big enough at the time to cut out the whole bell blank.

timothy42b wrote: Wed Jul 22, 2026 3:01 pm

NotSkilledHere wrote: Tue Jul 21, 2026 6:59 pm . Might make a difference in how bad someone's OCD gets triggered though!

CDO please. Alphabetical order is preferred.

NOW my OCD is triggered!

tbonesullivan wrote: Thu Jul 23, 2026 7:31 am

Doug Elliott wrote: Wed Jul 22, 2026 6:04 pmI have a Conn valve trombone with a Y seam.
With the insert I guess it stretches the sheet metal a lot less and requires fewer steps to make. I wonder why they stopped doing it that way. Appearance?

I have always wondered that. I assumed for Tuba bells it was either to save material, or because they simply couldn't get sheet brass big enough at the time to cut out the whole bell blank.

It's more about keeping the thickness uniform. Without the insert, the sheet would have to be stretched a lot more during spinning and it would get thin. And probably take a lot more time and more annealing.