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Shock-absorbtion


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Two things have come together to prompt a thought.

 

Last night I was being recorded at a friends and on play back found that I was hearing more clatter from the keys than I expected. I suddenly thought about the day before when Anne needed some new insoles for her hiking boots.

 

We went into a shop in Kettlewell in the Yorkshire Dales and selected a pair of insoles but they looked rather thin for the purpose - only 2mm thick and yet they claim to absorb over 98% of micro-shocks. The shopkeeper the gave a demonstration of how good they were by dropping a heavy ball-bearing onto them from a height of about 2 feet.

When he dropped it onto a normal insole the ball-bearing bounced 2-3 inches. On these special ones it hardly lost contact with the surface. The insoles go by the name of NOENE and if you google for it you will find a web site.

Apparently this material is now used on formula one racing cars under all the electronic packages and under on-board cameras.

 

It occurred to me that a layer of this material in a pad would help reduce the shocks and so reduce the clatter.

Does anyone have any opinions/experience of this sort of dampening?

 

Robin Madge

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The insoles go by the name of NOENE and if you google for it you will find a web site.

Apparently this material is now used on formula one racing cars under all the electronic packages and under on-board cameras.

 

It occurred to me that a layer of this material in a pad would help reduce the shocks and so reduce the clatter.

Does anyone have any opinions/experience of this sort of dampening?

Robin,

 

My "two hap'orth" would be that I wonder how long this material would last, compared with the life of a concertina ? (Most instruments are still on their first set of pads, even after 170 years.) And most of the "action noise" you typically hear is more in the levers and buttons, and endemic in Lachenal's.

Edited by Stephen Chambers
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It occurred to me that a layer of this material in a pad would help reduce the shocks and so reduce the clatter.

Does anyone have any opinions/experience of this sort of dampening?

In my experience, standard concertina pads don't "clatter", though I have had instruments where stiff, feltless replacement pads made noise. The clatter I've experienced has generally come from things like buttons without the felt circles at the bottom, or lever ends hitting the inside of the end when the button springs up, or -- most recently -- a bit of the button bushing being displaced, leaving the button to "knock" against the edge of its hole.

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Well most of my "clatter" seems to be coming from displaced felt bushing in the lever holes of my 1950s plastic with metal caps Wheatstone buttons.

However, I would think that the greatest cause of shock in the linkage, when it is set up with the proper tolerances, would come from the mass of the pad being brought to rest suddenly as it closes.

As to how the material will last, well this is always the question when you use a new material for the first time. It appears to have been around for about 10 years so far.

 

Robin Madge

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When you mentioned this material, I wondered if it was a brand name for a form of sorbothane, which is also used for very expensive vibration-absorbing insoles, and which hi-fi freaks rest their CD and vinyl record players on to insulate them from vibration. However a bit more web-searching and I discover that sorbothane is a polyurethane whereas noene is a synthetic rubber (which I think means it is a polybutadiene).

 

I once put some vibration-absorbing insoles in my shoes, and I didn't like it at all. Maybe it absorbed impact, but at the cost of increased rubbing as the foot moved around more within the shoe. As I have very soft skin on my feet, I got sores.

 

The connection between the pad and lever is quite wobbly, as it needs to flex to ensure a seal can be achieved. But you need to have a stiff layer or layers in the pad to ensure the pad remains spread out to cover the hole. Making sure the pad remains properly aligned to closes the hole properly, and doesn't foul adjacent pads, remains a regular maintenance task, even though I recently had it repadded etc. Would making the wobbly parts even wobblier improve this?

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Well most of my "clatter" seems to be coming from displaced felt bushing in the lever holes of my 1950s plastic with metal caps Wheatstone buttons.

Robin,

 

The actions in those 1950's Wheatstones use Lachenal levers in Wheatstone's own design of "hook action" post. The spring is serving two purposes, both keeping the pad closed whilst simultaneously keeping the lever bearing against its pivot. When you press a button, the lever initially breaks contact with the pivot before clacking back into place and raising the pad, hence a lot of clatter. The instrument would be a lot quieter if you changed it to having a riveted action.

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[When you press a button, the lever initially breaks contact with the pivot before clacking back into place and raising the pad, hence a lot of clatter. The instrument would be a lot quieter if you changed it to having a riveted action. quote]

 

This being the case, what Robin should do is wrap his wifes super absorbent socks around the tops of the wire pivots :) well maybe a very small piece of it or better still glue a sleeve of it around the levers where they make contact with the pivots

 

Unfortunately I doubt that changing to a rivetted action is an option.

Has anyone ever successfully done this?

 

Ian

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... what Robin should do is wrap his wifes super absorbent socks around the tops of the wire pivots :)  well maybe a very small piece of it or better still glue a sleeve of it around the levers where they make contact with the pivots

Ian,

 

I think that would probably result in a very "mushy" action ? :huh:

 

Unfortunately I doubt that changing to a rivetted action is an option.

Has anyone ever successfully done this?

Yes, the Concertina Connection do it on a regular basis, indeed they offer it as a standard repair option. They even have a web page devoted to it, if you follow this link and click on Replacement Action.

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I will vouch for the Concertina Connection's replacement action.

 

I bought the instrument from them with the action already replaced so I can't compare before and after. I do know it is fast, lightly sprung and a dream to play!

The action is so quiet that sometimes I have to look down and make sure that I am playing a Lachenal! (Although those taps and normal *gentle* Lachenal chatter can add a certain discreet charm to the music.)

 

If my instrument is typical of their valving and tuning and setting up an instrument to play, then I would give their work the highest of recommendations along with their replacement action.

 

Greg J

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Some addendum to the preceeding thoughts and comments:

 

Frank Edgleys concertinas have a hook and arm action but he has a neat way of double springing them that makes his concertina action smooth and quiet and light.

 

Goran Rahm says he has experimented for years with pad construction incorporating shock absorbant material and he likes the noise reduction.

 

There seem to be a number of opinions on whether hook and arm levers actually move at the pivot. There also seems to be different contentions as to whether, all things being equal, that hook and arm action must be more heavilly sprung than riveted action.

 

Any comments, opinions or data from the repairers and builders?

 

Greg J

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All I can say is that the action on my concertinas is light, fast and yet airtight. With some riveted action there is more friction as the lever has to move back & forth though the button hole where the felt gives some friction and, on the shorter levers can contribute to some stiffness as the arm toggles against the felt. The second spring at the fulcrum on my concertinas should prevent the mechanism arm from leaving contact with the fulcrum (the major source of Lachenal's noisy mechanism). Lachenal tried to solve this problem by using a very heavy spring to do both jobs i.e. hold the pad down and hold the lever against the fulcrum. However, it was not entirely successful. Due to the shape of the Lachenal lever arm it is not possible to add a second spring right at the fulcrum. My action has the advantage that it has no rivets to wear out which will eventually cause a noisy mechanism and need to be replaced. I had to replace some rivets on my Dipper a few years ago. It was a real pain as the fulcrum post had to be removed from the action board, the old rivet filed & punched out and the replacement rivet inserted and peened down. Then the whole mechanism had to be reglued into the action board. If a lever ever becomes noisy on my mechanism, all that's needed is to retension the spring by bending it open a few degrees.

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Rivets can wear out and also the hole in the lever can wear to the point where the lever breaks. I have a temporary lever made from a spectacle side-arm in one of my concertinas at the moment!

Perhaps with new materials there would not be so much wear.

Has anyone used PTFE for bearings etc.? It is used in the model railway fraternity and is available in tube form and also as a spray.

 

Robin Madge

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