Repair broken tines on Michelsonne?

[Andrea Kirkby]

I have had the great good fortune to find a rather distressed looking Michelsonne 37 key upright for a ridiculously low price at a sale. Some of the hammers will need replacing, but all the keys are there, though jumbled up inside the piano and not where they should be! 

That I can handle having repaired a few pianos before. But my problem this time is that three of the tines have broken off, so I'll need to replace them. I'll also need to manage to get the stumps that are left out of the retaining bar to make way for the new ones.

Does anyone have experience of replacing the tines? I really need a bit of help here. I have fortunately got a nasty cheap Chinese ten note piano to practise on, but I'm wondering what is the best approach:

• try to solder back the broken parts,
• drill out the 'stumps' and replace with fresh music wire using resin to bed in place.

I know that trying to knock the stumps out with a punch doesn't work, having tried that on the cheap Chinese piano. The only result was that one of the other tines cracked across the filed-down part and fell out. 

[Jean-David Beyer]

On 07/28/2015 01:54 PM, Andrea Kirkby wrote:
> I have had the great good fortune to find a rather distressed looking
> Michelsonne 37 key upright for a ridiculously low price at a sale. Some
> of the hammers will need replacing, but all the keys are there, though
> jumbled up inside the piano and not where they should be!
>
> That I can handle having repaired a few pianos before. But my problem
> this time is that three of the tines have broken off, so I'll need to
> replace them. I'll also need to manage to get the stumps that are left
> out of the retaining bar to make way for the new ones.
>
> Does anyone have experience of replacing the tines? I really need a bit
> of help here. I have fortunately got a nasty cheap Chinese ten note
> piano to practise on, but I'm wondering what is the best approach:
>

> * try to solder back the broken parts,
> * drill out the 'stumps' and replace with fresh music wire using resin

> to bed in place.
>
> I know that trying to knock the stumps out with a punch doesn't work,
> having tried that on the cheap Chinese piano. The only result was that
> one of the other tines cracked across the filed-down part and fell out.
>

I do not have a Michelsonne, but I do have a Schoenhut379. It the
Michelsonne is like mine, you are pretty much out of luck. While I do
not know for sure, it is my impression that the way the times are
inserted into the metal block is that the metal block is heated so it
expands, and the holes likewise, the tines inserted, and then the entire
assembly is allowed to cool. Unless you have the facilities to heat the
block in greatly heated oil (do not just try heating it with a propane
tourch) to perhaps 200*C, the only way to get the tines out would be to
drill them out with a suitable drill press, and the metal is so very
hard that you might use up even carbide-tipped drills.

I do not think you could solder the tines back together anyway. Lead-tin
solder is just too soft, so the sound would be bad, and it would not
hold on the steel very well. You might try silver brazing if you are an
expert at that kind of thing.

Even if you get the old rods out, without spoiling the hole size, and
even if you can find new Michelsonne rods (probably impossible), gluing
or trying to solder them into the old block will result in very bad tone.

Linda Michel Michelsonne on Facebook is the daughter of Victor Michel
who built the Michelsonne company. She might be able to help you, but if
you wish to get in contact with her, it would be better to write her in
French, German, or Alsatian. I am sure she is not in a position to
supply parts, but she knows many Michelsonne owners and may be able to
recommend someone.


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[Andrea Kirkby]

Thanks Jean-David. I may try silver solder as I have done a fair amount of metalwork.

But... I'm thinking, I have a block from the Chinese toy piano... if I can saw it up, I can possibly use the blocks and tines for the missing notes, screwing them to the back of the Michelsonne so the tines stick upwards instead of downwards - as long as they contact the hammers. That would save the piano. It's a bit of a bricolage, but better than a dead piano. And I can then tune the notes to fit. Does that make sense?

[Kent Swafford]

I have successfully replaced broken tines on a Michelsonne.

Heating was not required. I am fairly certain glues or solder would fail to repair a broken tine.

Note also that the vibration of the tines seems to require the solidity of the cast iron bar, and I think that breaking up that assembly into pieces would not yield good tone.

I punched out the broken stub, punching the broken stub from between the other tines, not the other way.

A new tine can be fabricated from 1/8” steel rod stock from the hardware store.

The hard part is that the neck must be narrowed in order for the tine to produce proper tone. Using a drill press, I was able to turn the rod sufficiently to narrow it. (Let’s just say I did not succeed the first time I tried this.)

After the neck is narrowed, the “stub” of the tine can be swedged and driven into the cast iron.

I have the benefit of a reasonably good shop. Proper tools do seem to be required for this work.

Kent Swafford

Registered Piano Technician

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