How to work in a tone chamber

[debra]

Dingo40,
I missed that picture of the 'cassotto' bending iron on the Hohner website. Thanks. A normal bending iron is a simple straight tool but of course there needs to be a bend on it for a cossotto situation.
Nobody has come back on my earlier mention of the cossotto design where one of the pallet levers was hinged with a spring. This allowed perfect automatic adjustment of the pallets and only the key height was left to be adjusted. Have I just dreamt this concept or should I be contacting the patents office now?

I never saw a spring-hinged lever design for use in cassotto.
Carini has a special cassotto bending iron. It's quite different from the one I showed because you don't have room inside the cassotto to use the one I showed.

 

[Deleted member 48]

Very interesting topic, working in a tone chamber.
Respect, I take my hat off for all those accordion repairers who are confronted with all sorts of differents accordion bass machines, mechanics, reedblocks inside tone chambers. Complex work for patient persons, must have the mindsetting of engineers to work with those ingenious mechanics.

In addition to textbooks, we could use more video tutorials.

Short video tutorials in Italian with English subtitles, an accordion with cassotto , tuning the clarinet and bassoon registers.




Accordatura clarinetto della fisarmonica



Accordatura del bassoon nella fisarmonica

 

[nagant27]

Not sure about this but could you work better inside the chamber and work on the pallets if you unscrew the metal piece enclosing the tone chamber? Then when your done with the pallets screw it back on. Would this break a seal? Or just not possible? I know I’ve seen quite a few screws on some that are metal. Wooden ones maybe not, I can’t remember.

 

[jollyrogeraccordions]

Great videos. Thanks. I have a couple of those long scratchers ( from Carini), they are the best, with a fine supremely sharp, hard point. Also I use the hook to get at the inside reed, like this chap (I’ve made several, of different sizes). In the first vid he briefly catches the adjacent valve with the file, which take practice to avoid. Also note he's doing the tuning by ear, which is as it should be, once you have the reference pitch set up. It doesn't do to get glued to the tuning software output. The really tricky tuning however is up at the high end, where the adjustments are minuscule and adjusting an inside reed can be tricky, with or without the cassotto. As a personal working practice i often start at the top, where it’s hard to get it right, and work down, where it gets progressively easier. The other way around and one is in danger of thinking you are nearly there, only to be faced with tricky high reeds esp piccolo reeds, and when you might be tired and wanting to stop.

 

[debra]

... As a personal working practice i often start at the top, where it’s hard to get it right, and work down, where it gets progressively easier. The other way around and one is in danger of thinking you are nearly there, only to be faced with tricky high reeds esp piccolo reeds, and when you might be tired and wanting to stop.

That's a very useful tip. I always start low, and work my way up, which indeed results in hitting the piccolo reeds when you are getting tired.
But I am kinda slow in any case so I tend to not reach the piccolo until the next day when I'm fresh in the morning. The main issue with being slow is keeping the room at constant temperature. The way tuning varies with a temperature difference of say 2 degrees (centigrade) really makes perfect tuning hard. (And I only do perfect tuning, not sloppy, "about right", or "you won't hear the difference" tuning...

 

[boxplayer4000]

DE4127042C1 - Key lever system for accordion - works against spring and has valve on one sector and second sector connected to key - Google Patents

Key lever works against a spring and has a valve on one sector and on a second connects to the key. A third sector angled relative to the second also carries a valve and forms a separate key lever which is hinged to the main lever and sprung into the valve-closing position. The leaf load spring...

patents.google.com

This patent document seems to refer to some sort of cassotto pallet self adjusting arrangement.
(This is an example of the difficulties of technical translation, which is the subject of a separate thread).

 

[Deleted member 48]

Inside Steirisch Harmonikas, sometimes tone chambers are also used, here is a patented Steirisch Harmonika with pics of the descant and bass side.
9 descant reedblocks inside tone chambers.

Cassotto 50/23 R, 4-reihig, 3-chörig von Rumberger Harmonika

Die Rumberger Harmonika Cassotto 50/23 R ist die erste 4-reihige, 3-chörige Steirische Harmonika mit Cassotto und Registerschaltung! Lassen Sie sich vom einzigartigen Klang verzaubern!

www.rumberger-harmonika.de

quote:
" Eine der größten Herausforderungen war außerdem die Umsetzung der Diskantseite. Auch hier war unser Ziel: maximaler Tonumfang – minimales Gehäusemaß. Daher sind im Gegensatz zu einer herkömmlichen Harmonika neun (!) Diskantstimmstöcke in der Cassotto 50/23 R verbaut. Diese Stimmstockverteilung war zwingend notwendig, um eine Luftkammernschaltung zu ermöglichen. "

 

[boxplayer4000]

My German is limited to ordering a beer but I think what you have highlighted is a different subject. ie. Your info seems to detail the reeds which are placed in cassotto while the topic I am pursuing is about the adjustment of the pallets in a cassotto situation. Perhaps a fluent German speaker will enlighten us.

 

[Deleted member 48]

My German is limited to ordering a beer but I think what you have highlighted is a different subject. ie. Your info seems to detail the reeds which are placed in cassotto while the topic I am pursuing is about the adjustment of the pallets in a cassotto situation. Perhaps a fluent German speaker will enlighten us.

The Rumberger Harmonika company integrated different innovations from the past and new ones that affect the reeds, the pallets, the reedblocks, tone chambers, even the big air release valve, etcetera ("wir haben die gröste Klappe", we have the biggest air release valve, ironically "we have a big mouth")
The design of the pallets that affects the construction and sound production inside the tone chambers, and the "Einzelklappen" influences the construction of the instrument. "wodurch das Umschalten der einzelnen Luftkammern erst möglich wird".

So I think it's not off topic when it comes to working in tone chambers.

Cassotto 50/23 R, 4-reihig, 3-chörig von Rumberger Harmonika

Die Rumberger Harmonika Cassotto 50/23 R ist die erste 4-reihige, 3-chörige Steirische Harmonika mit Cassotto und Registerschaltung! Lassen Sie sich vom einzigartigen Klang verzaubern!

www.rumberger-harmonika.de

quote:
"Die Diskantmechanik der Cassotto 50/23 R ist das Schlüsselelement und macht den entscheidenden Unterschied zu herkömmlichen Harmonikas. Diese Mechanik wurde von Grund auf neu entwickelt und war die größte Herausforderung beim Bau dieser Steirischen. Im Gegensatz zu Standardmechaniken mit Dreiecksklappen arbeiten wir mit Einzelklappen, wodurch das Umschalten der einzelnen Luftkammern erst möglich wird. "