heavier Miraphone tubas

[bloke]

I'm pretty sure that I've come to realize that latter-era Miraphone tubas feature considerably thicker gauge nickel bow caps,

which may explain part of the reason (along with larger diameter bells on the traditional models) that they seem heavier.

With older instruments, I'm often able to use (albeit 2", not 1") magnets to smooth out minor-to-medium denting through two layers of metal. With not-so-old ones, it's considerably more difficult, and often no possible.

[the elephant]

The new bow caps on my 1971 186 are thicker than the ones I removed. The old ones were 0.3mm (thinner than when new due to buffing, I am sure) and the new ones are 0.6mm (never buffed). I suspect the buffed "final thickness" is supposed to be about 0.5mm on new tubas. The new ones are indeed a bit thicker than the old ones.

[bloke]

I don’t like always being a contrarian, and here I go again.

It takes me a while to sand off 4 thousands of an inch off of something - much less buff that much off, and much less off of nickel silver.
I would more suspect that buffing those things (from their fine-sanded finish as they are shipped) removes a little bit of a thousandth of an inch, rather than nearly 4/1000’s.
Making some new tubes for my #3 slide on my model 98 has required a good bit of sanding and buffing of the inside slide tube pieces, and they still measure right about the same.

Nitpicking aside, I’m sure the new caps are thicker (just as are you sure), as they behave differently from the old ones, when working on them.
They are more dent resistant, but also more difficult to remove dents once they occur.

My F tuba caps are remarkably thin, and required amazing (factory) craftsmanship to install without denting them or chipping the edges.

[York-aholic]

It takes me a while to sand off 4 thousands of an inch off of something - much less buff that much off, and much less off of nickel silver.

I’ve got a 6x48 belt sander with a 40 grit belt that I’ll loan you if you’d like…

[bloke]

You need to proofread more carefully. You misspelled butt-sander.

It takes me a while to sand off 4 thousands of an inch off of something - much less buff that much off, and much less off of nickel silver.

I’ve got a 6x48 belt sander with a 40 grit belt that I’ll loan you if you’d like…

[jtm]

...
My F tuba caps are remarkably thin, and required amazing (factory) craftsmanship to install without denting them or chipping the edges.

the reason for those blasted sharp keels?

[bloke]

I think - over the years (in particular in the last century) - tuba players (OK… mostly males…so shake your finger at me) became taller, and more people ended up resting tubas in their laps, rather than on their chairs.

The tall heels were thin – again – to avoid them being excessively heavy.
In the past, a large number of these instruments were three valve, and were mostly marched with using a braided rope around the shoulders as a strap.
I really believe the thinness had nothing to do with the sound, and had everything to do with marching.

[Mary Ann]

I would think the thinner metal would be more prone to "acciDENTs" during the making of them, and that the thicker metal is not so susceptible.

[bloke]

Yes.
I know that it takes considerably more craftsmanship to build thin wall instruments – instruments that (out of ignorance) some judge to be “cheap“.
I know this because it takes considerably more craftsmanship to REPAIR thin wall instruments.