Reed Blocks with a CNC

[ivangunkel]

Hi, I'm new here on this forum and I found him doing my research on the internet. I am very happy to be here and acquire knowledge.

I'm Brazilian, and I'm on an ambitious project, recreating the reed block of a Todeschini accordion (Brazilian).
I acquired a Galanti accordion from the 50s / 60s that has the highest quality reeds, timbre and volume, and I am redoing the reed blocks to put on my Todeschini.

The idea is to use a CNC machine, in order to make the reed block in a solid block of wood, as the old Scandalli were made, I believe that this should add firmness to the sound, since there is much less glue and wood joining.

Making reed blocks for bass was easier, as they all obey the same depth. In the right hand, this depth should decrease as the reeds get smaller. There is no document that describes an ideal reduction size, at least I haven't found it.

The reduction I made based on Galanti's reed blocks.

Basson starts with 10mm and ends with 5mm.
Clarinet/Flute starts with 8mm and ends with 4mm.
Piccolo starts with 7mm and ends with 1mm.

I wonder if anyone on this forum would have anything to share about it. We know that a reed can never hit the bottom of the reed block, but what is the ideal depth? what is the ideal reduction design? Which promotes more volume? Does a larger cavity change the timbre?

These are doubts that I have and that any help would be welcome.

Attached are some photos of my work.

Thank you and good work to all!

 

[Dingo40]

Welcome Ivan,
I admire your energy and enterprise!
Good luck with your project!??

 

[Ventura]

excellent work Ivan, and i wish you continued success

reverse engineering to learn how to build something is fun, but
also limited by the fact that figuring out a WHY is much harder
than figuring out HOW

the Scandalli SIlvetta is the specific instrument the Chinese 100%
reverse engineered and which they have since produced hundreds of
versions of (sort of) accordions and accordion shaped objects
from the knowledge they gained

You are doing quite better than they did, i think, you seem to have
some real wodworking skills and understanding and a more noble Goal

SO what i can suggest to your inquiry are 2 things

do not be totally resistant to Glue, as the type of Wood you could
select to mill out for the Chambers is PROBABLY NOT the best type
of wood to use as the BASE, because you are striving to take advantage
of the woods properties, and there are two very different needs
between the BASE and the CHAMBERS

the base piece of wood needs to be a very strong dimensionally stable type
that can be sanded to a super smooth and dead FLAT surface that will
remain absolutely stable, and never allow it's grain to raise

regarding the individual chambers, i have seen a number of Pre-WW2
reedblocks from made in New York accordions that were milled from solid pieces,
and something i noticed were that the interior area of the individual chambers were
NOT angled, but had more curvature and were nicely polished and very smooth inside

these also had round hole bottoms to present to the air flow from the valves

some of the reedblocks in your pictures show all severe right angles inside for the
air and sound to bounce off, and i wonder if perhaps they had an advantage
in those very old days with the more rounded insides... an advantage we
have lost with modern matchstick reed-block construction ?

i am thinking the sharp angles and dead flat surfaces would push BACK with impedence
against the reed flexing whereas these off-axis reflective surfaces would act differently
buffering the air and vibrations with indirect reflections

BUT THIS IS JUST SPECULATION on my part

however, the idea of an Empirical approach means you could mill both kinds of
reedblocks and test and compare !

though you might need to make the reedblock a small bit taller to allow for a curvature
at the top inside dimension

best of luck !

ciao

Ventura

 

[debra]

In addition to different wood for the base and the chambers I have also seen reed blocks where the "wall" in the center (separating the sound of the two sets of reeds) is yet another type of wood...

 

[ivangunkel]

excellent work Ivan, and i wish you continued success

reverse engineering to learn how to build something is fun, but
also limited by the fact that figuring out a WHY is much harder
than figuring out HOW

the Scandalli SIlvetta is the specific instrument the Chinese 100%
reverse engineered and which they have since produced hundreds of
versions of (sort of) accordions and accordion shaped objects
from the knowledge they gained

You are doing quite better than they did, i think, you seem to have
some real wodworking skills and understanding and a more noble Goal

SO what i can suggest to your inquiry are 2 things

do not be totally resistant to Glue, as the type of Wood you could
select to mill out for the Chambers is PROBABLY NOT the best type
of wood to use as the BASE, because you are striving to take advantage
of the woods properties, and there are two very different needs
between the BASE and the CHAMBERS

the base piece of wood needs to be a very strong dimensionally stable type
that can be sanded to a super smooth and dead FLAT surface that will
remain absolutely stable, and never allow it's grain to raise

regarding the individual chambers, i have seen a number of Pre-WW2
reedblocks from made in New York accordions that were milled from solid pieces,
and something i noticed were that the interior area of the individual chambers were
NOT angled, but had more curvature and were nicely polished and very smooth inside

these also had round hole bottoms to present to the air flow from the valves

some of the reedblocks in your pictures show all severe right angles inside for the
air and sound to bounce off, and i wonder if perhaps they had an advantage
in those very old days with the more rounded insides... an advantage we
have lost with modern matchstick reed-block construction ?

i am thinking the sharp angles and dead flat surfaces would push BACK with impedence
against the reed flexing whereas these off-axis reflective surfaces would act differently
buffering the air and vibrations with indirect reflections

BUT THIS IS JUST SPECULATION on my part

however, the idea of an Empirical approach means you could mill both kinds of
reedblocks and test and compare !

though you might need to make the reedblock a small bit taller to allow for a curvature
at the top inside dimension

best of luck !

ciao

Ventura

Hello Ventura, thanks for the reply and tips.

Only the block where the voices are housed is made of solid wood, the base is of another, more dense variety of wood.

Here in Brazil it is almost impossible to have access to the Abeto and Mahogany, but I used a wood called Marupá, which among studies was defined with the density closest to the Abeto. The base is made of Imbuia, a very dense and resistant wood, in order to avoid warping the reed block.

The accordion board has rectangular holes, so I need to keep the same design as the reed block.

I would like to take this opportunity and ask if someone knows the type of finish that is given internally on the accordion, walls and reed blocks are painted with a type of varnish, but it is probably not a common varnish. I know that the goal is not only to seal the wood and preserve it, but also to help dissipate the sound. Does anyone know what varnish it is?

Thanks to all for your help

 

[ivangunkel]

In addition to different wood for the base and the chambers I have also seen reed blocks where the "wall" in the center (separating the sound of the two sets of reeds) is yet another type of wood...

Yes, you are correct. When the frames are assembled with pieces of wood, usually the fondo is made of dense wood, the divisions are made of lighter wood, and the base and the top of a more dense wood, in order to give consistency to the construction of the whole.

In the case of an entire block of wood, such concerns are not necessary, as the structure is naturally stronger. However, the wood used in the base must always be dense, in order to prevent it from warping.

Thank you for your help!

 

[jozz]

Yes, you are correct. When the frames are assembled with pieces of wood, usually the fondo is made of dense wood, the divisions are made of lighter wood, and the base and the top of a more dense wood, in order to give consistency to the construction of the whole.

In the case of an entire block of wood, such concerns are not necessary, as the structure is naturally stronger. However, the wood used in the base must always be dense, in order to prevent it from warping.

Thank you for your help!

Check out this --> video

This is a renowned Dutch harmonica builder where he explains "it gives a little bit better sound" when he went the opposite way from a completely CNC milled block to a hybrid block with inidivual glued partitions, keeping the grain lenghtwise. The backbone and roof of the block is till CNC'ed out of one piece.

In other interviews (Dutch), he goes as far in detail as stating: specific teak is better for Irish music, maple is better for French.

 

[Pipemajor]

Check out this --> video

This is a renowned Dutch harmonica builder where he explains "it gives a little bit better sound" when he went the opposite way from a completely CNC milled block to a hybrid block with inidivual glued partitions, keeping the grain lenghtwise. The backbone and roof of the block is till CNC'ed out of one piece.

In other interviews (Dutch), he goes as far in detail as stating: specific teak is better for Irish music, maple is better for French.

I notice, in the interview, he says he puts the highest reeds in upside down.
Is this standard practice and is it worth while changing them if they are in the normal way?

 

[jozz]

I notice, in the interview, he says he puts the highest reeds in upside down.
Is this standard practice and is it worth while changing them if they are in the normal way?

I'm no expert, but to me it looks like he deliberately makes the caveties of those higher reeds smaller (you can see there is an offset in the wood in those). Possibly for more direct response?

Therefore needing to place them upside down, leaving room for the tongue to swing.

So if you don't have your caveties like that, I suppose there is no use doing that.

 

[Glug]

I've noticed that on my 1950s Scandalli.
On the H reed bank C6 and above have no valve, B6 and above are upside down.

 

[ivangunkel]

Check out this --> video

This is a renowned Dutch harmonica builder where he explains "it gives a little bit better sound" when he went the opposite way from a completely CNC milled block to a hybrid block with inidivual glued partitions, keeping the grain lenghtwise. The backbone and roof of the block is till CNC'ed out of one piece.

In other interviews (Dutch), he goes as far in detail as stating: specific teak is better for Irish music, maple is better for French.

Wow, very instructive indeed. Thanks for the tip. I will try to contact him, maybe he will help me with some things.

I notice, in the interview, he says he puts the highest reeds in upside down.
Is this standard practice and is it worth while changing them if they are in the normal way?

In most piano accordions, the piccolo octave is positioned this way, the last 8 or 12 voices are reversed. In addition to helping with the response, it is also more practical to make the tuning touch-up inside the instrument, the final fine adjustment.