Probably naive question about reeds

[paulbrennan]

So -  in the case of reeds mounted on long plates - do the tongue and the reed plate *have* to be separate objects? What if you took a piece of appropriately fine steel sheet and cut out the *outline* of a reed tongue, while leaving the base of the tongue attached to the plate - would this vibrate under the right conditions? I guess it would still have to be mounted properly on a suitable reed block (which could be made of various materials), and air pressure applied. Would this eliminate the problem of riveting, aligning and gapping the reed? My assumption is that this wouldn't work but I can't explain why not. 

 

Kind regards, Paul

Edited November 28, 2022 by paulbrennan

[wunks]

I've thought along these lines myself; why the reed and shoe or plate can't be all of one piece, perhaps 3d printed?  Is a hard plastic reed/shoe workable?  We're admonished to not tamper with those two little screws holding it all together, why not combine functions?

Edited November 29, 2022 by wunks

[Steve Schulteis]

Aren't some Chinese free reed instruments made by making a cut to create the tongue and shoe from the same sheet?

[paulbrennan]

14 minutes ago, Steve Schulteis said:

Aren't some Chinese free reed instruments made by making a cut to create the tongue and shoe from the same sheet?

Like the sheng? Yes it looks like. 

[Owen Anderson]

I'm purely speculating as I have no experience making reeds.

 

I suspect that there's something about the material properties that impacts this. The reed is meant to flex, and the shoe is not. Presumably the difference in materials between the shoe and the reed contributes to ensuring that this is the case, as would things like intentional grain misalignment between the two materials. A unitary reed and shoe would lose those benefits. I also suspect that, for a mass-produced item like an accordion reed, the machining required to make a unitary reed wouldn't be able to deliver as smooth a reed tip as electro-abrasion does, which would impact the sound.

 

Which is not to say that it's impossible, but I suspect there's a lot to be figured out before it's clear if it's possible to make a good unitary reed.

 

 

[alex_holden]

1. If you made the cut with a saw, you'd get quite a large gap between the two parts, which would make it inefficient and unresponsive. Shearing would be difficult to control (particularly ending the split in exactly the right place) and would probably result in no gap at all between the parts, so you'd then have to remove a small amount of material along the full length of the split to form some clearance so the reed could pass freely through the slot (tricky when you can't separate the two).

2. Reed tongues need to be profiled, i.e. their thickness varies significantly along their length and every pitch has a different profile. This would be difficult to do if the frame was in the way.

3. Generally you want the frame to be much thicker than the root of the tongue, because the tongue needs to be flexible but the frame should be rigid. With traditional concertina reeds the frame is typically 2mm thick and reed tongues are less than 0.5mm at the root.

4. There are some advantages to making the reed tongue from hardened spring steel and the frame from a much more easily machined material like aluminium alloy or brass.

 

I'm not saying it's impossible, but it suspect it would be considerably more difficult than the way they are normally made.

[Wally Carroll]

Alex covered this pretty well. I would just add that the depth of the reed shoe and the flaring on the underside is needed to get everything to work and sound like a concertina. To Alex’s first point: the gap is usually .001” or less between tongue and frame.  I’m not sure what technology exists in order to create a gap this thin in a single piece of spring steel but I’d be happy to be educated on this front. The wire EDM I use is .008” which would produce a kerf closer to .009” going through spring steel.  

[Owen Anderson]

5 hours ago, Wally Carroll said:

Alex covered this pretty well. I would just add that the depth of the reed shoe and the flaring on the underside is needed to get everything to work and sound like a concertina. To Alex’s first point: the gap is usually .001” or less between tongue and frame.  I’m not sure what technology exists in order to create a gap this thin in a single piece of spring steel but I’d be happy to be educated on this front. The wire EDM I use is .008” which would produce a kerf closer to .009” going through spring steel.  

 

Harvey Tools makes a 0.001" end mill, which would get you close, though good luck getting a smooth finish on that.

[alex_holden]

1 hour ago, Owen Anderson said:

 

Harvey Tools makes a 0.001" end mill, which would get you close, though good luck getting a smooth finish on that.

 

With a maximum 0.003" depth of cut, assuming it doesn't snap when you breathe near it.

[Clive Thorne]

A YAG laser with the the right optics might get you down to a 1 thou /25u cut, but not a cheap process as it would need to be configured specifically for this type of work.

 

As for the 1 thou end mill, do you buy them in packs of 1000 to account for breakages?