Brass rods between reed blocks

[TomBR]

Those who have seen them will know what I'm talking about. I've mainly worked on Hohners so I don't know if other makes have them, but sometimes there are small brass rods linking one reed block to the next. They're not screwed or fixed and would fall out under tension - they just rest in a small hole at either end.

Anyone know what they're for, why they're there?
I can't imagine any structural function, so my guess would be that they're either to reduce unwanted resonance, or promote beneficial resonance. Help synchronise reeds on the other reed block by transferring vibration at the top of the reed blocks?

(I now realise I haven't noted which blocks are connected. As I recall the rods are nearer the bass end.)

I put them back if I have to remove them but it would be nice to know why they're there! A manufacturer like Hohner doesn't add extra parts without a reason!
Tom

 

[JIM D.]

When you find these so called alignment rods you can be sure you have an accordion that uses an outdated primitive reed block design and requires these rods for support. Some German makes have been made with these in the recent past and you can find this practice used on currant China makes. JIM D.

 

[Jim the box]

I must admit I’ve often wondered why reed blocks are tied together myself sometimes just by clips that secure one end and loop over the other. :?

The reed blocks seem rigid enough on their own.

 

[TomBR]

Can you tell us any more about the support function Jim? I don't quite get it in the context of a little unsecured rod and quite substantial reed blocks.
Thanks,
Tom

 

[JIM D.]

Unlike high end (and high priced) accordions that have components made from hardwoods that are aged from 10 to 15 years. Lower priced brand models are made from woods that are not aged, soft, and will tend to warp and or shrink with age. These so called braces are installed to keep the blocks from warping as they age in the accordion. If you find an an accordion with these so called braces that is more than 20 years old I advise you keep them in but they really are no longer necessary. JIM D.

 

[Jim the box]

Unlike high end (and high priced) accordions that have components made from hardwoods that are aged from 10 to 15 years. Lower priced brand models are made from woods that are not aged, soft, and will tend to warp and or shrink with age. These so called braces are installed to keep the blocks from warping as they age in the accordion. If you find an an accordion with these so called braces that is more than 20 years old I advise you keep them in but they really are no longer necessary. JIM D.

Thanks Jim, you really do learn something everyday. :ch

 

[kimric]

Um, those rods are not for support.
You will mostly see them in button boxes or other smaller instruments with lighter/ smaller blocks.
The reason they are there is because often secondary harmonics will cause reeds to stop playing, or be out of tune when they are in the accordion, but not while they are on the tuning table.
The braces use the combined mass of the reeds and blocks to damp out this effect. Not a quality issue ,as you will see these in everything from Parrots to Gabanelli accordions.

 

[JIM D.]

Yes, you can find bracing in some top end boxes and the makers of these models claim just what you state in your post. But the fact is 98% of the time these rods and braces are to keep small or weak reed blocks in alignment. JIM D.

 

[TomBR]

Yes, you can find bracing in some top end boxes and the makers of these models claim just what you state in your post. But the fact is 98% of the time these rods and braces are to keep small or weak reed blocks in alignment. JIM D.

Sorry Jim, I just dont find that convincing in the context of the brass rods I was referring to in my original post.
The way they are mounted means they give zero support in tension, and very little in compression. If the intention was structural Id expect something like a wooden or metal strap screwed at both ends.
Then again, lots of reed blocks have no bracing. If it was an issue related to quality of materials, why dont they? One could imagine bracing to the sides of the case if it were necessary.
Quite happy to be proved wrong - any sources you can point to?
Tom

 

[JIM D.]

At this point I'm afraid I have to, from past experience, stick with my personal opinion that any braces or connecting rods used to control warping or tonal vibrations are just a crutch to correct a poorly or flawed design.

 

[TomBR]

Fair enough Jim, thanks for your replies on this.
Tom