Hand-hammered bell?

[jtm]

Is it possible to tell by inspection (rather than knowing about the particular model/year) whether a tuba bell was formed by hand?

[Schlepporello]

Is it possible to tell by inspection (rather than knowing about the particular model/year) whether a tuba bell was formed by hand?

There's not a machine that a shop can use that has a button marked "Bell". They all have to be hand-formed to a point, then spun on a metal lathe for forming. Go to YouTube and you can find many references there on how tubas are built.

[bort2.0]

I don't have the links handy... But the Miraphone videos are great. There's also a 3-partset of videos from B&S,where Jon Sass leads a tour throughthe factory. Fun to watch them make the B&S bells!

[bloke]

Unless a bell is manufactured by the copper-plating-onto-a-mandrel method - or made of something other than metal - something is going to need to hammer the seams flat...whether that’s someone’s arm holding a hammer, or whether it’s a machine - with a person positioning the seam underneath the hammering point of the machinery. Even laser/plasma welded seams don’t begin their lives as being nice and smooth and flat.

[bone-a-phone]

Bells and other components can be hydroformed. From a practical point, though I think the bell flares are easier to spin, and the asymmetrical parts like bows on cheaper instruments are done using hydroforming. My day job is mechanical engineering, so this sort of question is the natural intersection of my work and play.

This is the basic idea with hydroforming:


This is a general demo of hydroforming, and you can see how it would be applied to brass instrument parts.
[youtube]https://youtu.be/XUMs3cWBlks[/youtube]

In this Wessex movie it shows automated bell flare spinning at about 0:20 and then hydro forming a bow at :46
[youtube]https://youtu.be/kc7AxeVgrMA[/youtube]

This shows general bach trumpet bells being produced using a combination of machine and hand work
[youtube]https://youtu.be/hcVlISP-3ak[/youtube]

instrument manufacture play list:
https://www.youtube.com/playlist?featur ... 194BDAAFD5

Of course none of this answers your question. The only way you can tell a hand formed tuba from a machine formed tuba is to look at the price. The price and the weight. High price, low weight, hand formed. Low price, high weight, machine formed.

[jtm]

I gave up real engineering to build software, so what's the advantage of hydroforming vs. a fixed top form, besides only needing one die?

I can't find the comments now at the old place, but I seem to remember bloke saying that some tubas (say, Miraphones of a certain vintage) could sound better because there was more handwork done on the bells. Quite possible I'm misremembering, though.

[bone-a-phone]

I gave up real engineering to build software, so what's the advantage of hydroforming vs. a fixed top form, besides only needing one die?

I can't find the comments now at the old place, but I seem to remember bloke saying that some tubas (say, Miraphones of a certain vintage) could sound better because there was more handwork done on the bells. Quite possible I'm misremembering, though.

Hydroforming a bow uses top and bottom dies, plus end plugs, and then pressurizes the inside. This smoothes out the tube. If you formed a bell with two dies, the top die would leave scratch marks from metal to metal contact, and the self-leveling pressure of hydro makes the metal smoother.

Hand work work-hardens the material. harder material means you need less of it, and of course harder material resonates differently (more upper overtones). Hydroforming minimizes work hardening, so the material is probably softer, and needs to be thicker, or reinforced. Thicker/softer leads to a dull sound.

[hrender]

Hand work work-hardens the material. harder material means you need less of it, and of course harder material resonates differently (more upper overtones). Hydroforming minimizes work hardening, so the material is probably softer, and needs to be thicker, or reinforced. Thicker/softer leads to a dull sound.

This.

[Doc]

Hand work work-hardens the material. harder material means you need less of it, and of course harder material resonates differently (more upper overtones). Hydroforming minimizes work hardening, so the material is probably softer, and needs to be thicker, or reinforced. Thicker/softer leads to a dull sound.

This.

So... with what instruments can we make real-world comparisons?

I've played a number of recent 186 CC's, and I owned one for a while and NONE of them play anything like the 1969 blokeified 186 I have now. My assumption/guess/best I can tell is because the newer 186's don't have the extensive handwork that the vintage ones do. Same with Symphonie F tubas vs. new B&S F tubas, yes? What others?

Advantages vs. Disadvantages?

And how much more handwork actually goes into Hagen 497 bells and Siegfried bells compared to 496/495/etc. bells?

[pjv]

As far as I understand the Miraphone 497 en 98B have hand hammered bottom bows (I don't remember them mentioning the bells, so check me on that). Someone once suggested (Herr Kline??) that the bottom bows were even hydro formed, THEN hammered just to thin them out. A modern, cheeper way of creating a more responsive horn.

Something like that.

[bloke]

One way that funny-shaped (not symmetrical) saxophone bells are formed is by pulling a lead donut through them (in a steel mold) with a chain. The donuts are then thrown in a barrel, melted back down again, and reformed to be reused an infinite number of times...

...but - before the donuts are pulled through those bells in those molds - they still need their seams hammered flat.

[Doc]

As far as I understand the Miraphone 497 en 98B have hand hammered bottom bows (I don't remember them mentioning the bells, so check me on that). Someone once suggested (Herr Kline??) that the bottom bows were even hydro formed, THEN hammered just to thin them out. A modern, cheeper way of creating a more responsive horn.

Something like that.

I've never asked the folks at Miraphone, Richard Murrow, or Roger Lewis, but I'm curious (tangental, I know): Besides bell and bottom bow, how else do the 497 and 496 differ? Top bow? Valve set? Lead pipe? Is everything different after the valveset or just certain parts?

Doc (who hopes he can do a real, in-person, side-by-side comparison before the year is out)

[bone-a-phone]

So... with what instruments can we make real-world comparisons?

As I understand it, some of the Wessex tubas are the same with the only difference being some are hand made and some are hydroformed. I'm not sure I've got the models correct, but the Prokofiev ($9750) https://wessex-tubas.com/collections/bb ... fiev-tb693 and the Grand ($5450) https://wessex-tubas.com/collections/bb ... rand-tb692 seem to be paired this way.

[bone-a-phone]

One way that funny-shaped (not symmetrical) saxophone bells are formed is by pulling a lead donut through them (in a steel mold) with a chain. The donuts are then thrown in a barrel, melted back down again, and reformed to be reused an infinite number of times...

...but - before the donuts are pulled through those bells in those molds - they still need their seams hammered flat.

...unless it started as a large diameter drawn tube. The same processes are used for saxes as for tuba bows. Trombone tuning slide crooks can be created from flat seamed sheet or from drawn tube expanded as you mention or expanded and bent by hydroforming.

Yeah, there's nothing such as fully machine made instruments. It's always some combination of manual and machine processes. Just some processes are more machine than man. Unless it's fully manual with just hand tools, but even then the sheet brass is produced by big machines.

Bell flares can be hand spun, machine spun, stamped, electroformed or hydroformed. Hand spinning still requires a lathe.

[Wyvern]

So... with what instruments can we make real-world comparisons?

As I understand it, some of the Wessex tubas are the same with the only difference being some are hand made and some are hydroformed. I'm not sure I've got the models correct, but the Prokofiev ($9750) https://wessex-tubas.com/collections/bb ... fiev-tb693 and the Grand ($5450) https://wessex-tubas.com/collections/bb ... rand-tb692 seem to be paired this way.

Actually there is more different than just how those two tubas are made. They each have different profiles. The Prokofiev bell is based on a York, while the one for the Grand is based on a Holton.

Hand hammered tubas tend to be lighter, as thinner metal can be used, as the walls will be even thickness, while hydro formed tubas will naturally be heavier, as the metal needs to be thick enough to stretch - so wall thickness will vary on inside and outside of bow for example.

[bort2.0]

I've heard it as the when the tubing is expanded hydraulically, the near end will be thinner (since it's closer to the initial force of the water) and the far end is thicker (father from the force, and gets expanded less). Cumulatively, the thin/thick joints throughout the tuba make it less even than it could be with hand-formed tubing throughout ... So the handmade stuff is more.even in that way.

But, hydraulic is much faster and more predictable, and more consistent in the results. When things are made by hand, there is less consistency... Whose hands? And which days? Are one set of hands the same as another? So many variables... We joke about having "one of the good ones," but that is just sort of how it goes when everything is handmade and done individually. Hydraulic forming helps make a more consistent, but slightly different, product.

Which is better? Could be either and construction method might not even matter at all in the end. Try, buy, play, decide after a month. Thats how I do it.

[bloke]

If a bow is made of seamed sheet metal, it can be made tapered, formed and not expanded.

Typically, hydraulically-expanded bows began as cylindrical tubing.
The smaller end (having been expanded less) is going to be thicker, and the larger end (having been expanded more) will be thinner.
To make a hydralically-formed instrument more like "handmade", someone - whose very sensitive with a belt sander - can sand more heavily on the thick end and less-to-none on the thin end, so that they entire bow ends up closer to the same thickness - from one end to the other.

[pjv]

As far as I understand the Miraphone 497 en 98B have hand hammered bottom bows (I don't remember them mentioning the bells, so check me on that). Someone once suggested (Herr Kline??) that the bottom bows were even hydro formed, THEN hammered just to thin them out. A modern, cheeper way of creating a more responsive horn.

Something like that.

I've never asked the folks at Miraphone, Richard Murrow, or Roger Lewis, but I'm curious (tangental, I know): Besides bell and bottom bow, how else do the 497 and 496 differ? Top bow? Valve set? Lead pipe? Is everything different after the valveset or just certain parts?

Doc (who hopes he can do a real, in-person, side-by-side comparison before the year is out)

I checked some notes I made when I was at the factory in 2018. This is what I wrote down:
"Siegfried and Hagen 497 are almost the same partially hand-made instruments and share almost all of the same parts.
Difference: Bell is larger on the 497 but the mouthpipe starts smaller. The mouthpipe on the Siegfried and the 497 are hand bent. Between the valves the knuckles make sharp angles (not rounded like the Siegfried).
497 and 496 are the same until after the valve section where the 496 moves on towards a smaller bell. The 496 is for the rest not hand-made (as far as I know)."

[Doc]

As far as I understand the Miraphone 497 en 98B have hand hammered bottom bows (I don't remember them mentioning the bells, so check me on that). Someone once suggested (Herr Kline??) that the bottom bows were even hydro formed, THEN hammered just to thin them out. A modern, cheeper way of creating a more responsive horn.

Something like that.

I've never asked the folks at Miraphone, Richard Murrow, or Roger Lewis, but I'm curious (tangental, I know): Besides bell and bottom bow, how else do the 497 and 496 differ? Top bow? Valve set? Lead pipe? Is everything different after the valveset or just certain parts?

Doc (who hopes he can do a real, in-person, side-by-side comparison before the year is out)

I checked some notes I made when I was at the factory in 2018. This is what I wrote down:
"Siegfried and Hagen 497 are almost the same partially hand-made instruments and share almost all of the same parts.
Difference: Bell is larger on the 497 but the mouthpipe starts smaller. The mouthpipe on the Siegfried and the 497 are hand bent. Between the valves the knuckles make sharp angles (not rounded like the Siegfried).
497 and 496 are the same until after the valve section where the 496 moves on towards a smaller bell. The 496 is for the rest not hand-made (as far as I know)."

Thank you.