Piano World Home Page Forums Our Most Popular Forums Piano Tuner-Technicians Forum Ok, so I've been thinking about Max's cardboard fix

Johnkie, if you will not be difficult to write a "French chalk" about. is it a talc? How it is used (in) with a wrestpins? Rub a pin "French chalk" before a hammering in a wrestplank?

I just sprinkled the usual chalk a corrugated cardboard shim before installation. Tried it with only one pin. I'm tighten(turn) the pin that was no more difficult than without the chalk by Max's method when I became it's tune, it is very difficult to turn over into the pinblock and a pin a little squeak. After 2 days of pin has not loose but I did use the chalk will not, because what happens super friction. It's a pin very difficult to tuning.

"French chalk" is not really chalk it is a stone which contain calcium and clay.
http://en.wikipedia.org/wiki/Marl
it may probably provide less friction.
Thank you for the witnessing.

Russian version :
http://ru.wikipedia.org/wiki/%D0%9C%D0%B5%D1%80%D0%B3%D0%B5%D0%BB%D1%8C

Isaac,I agree if we use any (chalk, rosin, French chalk, sandarac) or perhaps a mix based on them should be guided by the actual state of the friction between the pins and a pinblock. Perhaps the French chalk on the basis of alcohol would provide a mild state of screwing with a shim, if rub loose pin when reinstalling it's. It may be unnecessary to resort to using corrugated a shim. The main is to in the time reinstall the pin did not issued a squeak. And when tuner be tuning the piano a pin must moved smoothly without jerking into a pinblock

If the pin squeak (crack) you need better technique to tune, but you are sure that it will not move anymore. A good piano often cracks when the pitch is raised

Poor pin setting or lack of technique give the impression that the block does not hold well enough.

But it is possible to tune even with little holding of the pin. (I believe I did not use any shim for years)

What makes it difficult is when there is much friction under the string (grand pianos) and marks in the agrafes.
the part of string in front of the pin have to be tense the same than the pin and the same as the rest of the string, so if you cannot manipulate it smoothly tuning is difficult.

Unfortunately, I have not a lot of practice with the grand piano. But, Isaac you have to be right when writes that as a result of proper technique work with pins, even irretrievably lost pin suddenly begins to to fix as good. I had to experience this feeling with a grand piano name "Красный Октябрь". Initially a few pins after a short time lost friction, but after a few my approaches to the Grand and a repeat it's tuning , a miracle! A pins began to to stand as need. I had deliberately inflated step, it's are dispensed before the desired the moment

I would like to add a bit of info to Max's post about the cardboard shims. In the mid 80's when I finished my technicians schooling, I travelled to central eastern Europe and spent some time in several (at that time communist ruled) countries gypsying around (and visiting relatives). I had my tuning lever and some minimal tools with me and tuned pianos wherever I went, just for the experience and exposure to European instruments. Toured many restoration and piano rebuilding businesses also.

Well I came across many pianos that had slips of plain paper used as shims to tighten up the grip on loose pins. I aquired the practice myself as it was ridiculously difficult to aquire any specialty items for the trade at the time. Long queue lines were normal at that time for even simple commodities.

Sometimes I seen shims of thicker material, like what postcards and shoe boxes were made from, other times a single piece of paper was folded in half to provide more grip. Interestingly, several of these pianos I visited a decade later and the fix was still working fine. Its not a short term fix, if done correctly.

Also, sometimes if one wishes to use a wood shim, they become brittle if they are as thin as paper. On a marginally loose pin that would become too tight with the thinnest wood shim, paper is a good solution. Cardboard on the other hand may work better than folded paper when the pins are very loose, as max has demonstrated.

Years later, working in tool and die, I found that paper was a perfect material to put between thin metal parts and the surface grinders magnetic table. Without it, the magnetic grip was not strong enough to secure the thin parts. The coefficient of friction is much higher between paper and metal than it is for metal on metal. This process is used all the time in the trade to solve this problem.

Dear Emmery, a tears roll down my cheeks. But it's tears caused by a feeling of joy, corrugated cardboard shim is not Max's focus of, but the real thing. It's capable of effectively strengthen (tighten up) loose piano's pin. Emmery, thank you for those good words. What you have written is YOUR theoretic, a practice way"
Regards from Max

Thanks Emmery for witnessing your experience, Yes I was surprised to have a good feel under the lever, with the cardboard, but once the pin is took of only dust is left in the hole. I had no opportunity to make more testing, but it is intended with next strings change

So it is widely used in East Europe. Interesting that different thickness/material face different situations.
Sure wood shims get crushed in the block

for lower tensions harpsichord and forte pianas I

know that brass shims are doing the job better than wood shims, for what have been told me.

Isaac,the thickness of corrugated cardboard shim depends , as you rightly have noticed depletion of the holes in the pinblock. I can not advise to use in all cases, 3 mm corrugated cardboard. Perhaps in some cases, this thickness is 1.5 mm, if the pin is not completely loose a friction . Required thickness shim must determine myself technic,which it's to set
I have written repeatedly before, that the dust that you found in the hole's of pinblock is inevitable. While as we turn a pin into a pinblock a shim is partially destroyed and cellulose dust remains in the hole. Much of this dust, pressurized hot a pin penetrates into the cracks of a pinblock to filling it. Therefore, this cracks can be roughly considered as recieved repaired and been sanded. Undisturbed a part of the shim works as a classical shim for wedging.
If I understand you, then you have already conducted tests with a cardboard shim. Isaac, when you repeat this operation in a future please describe how it was.
Regards, Max

Max, I believe that the hole may not be cracked, but only too much compressed, hence low elasticity of the wood and too much space between the pin and the block.

Due to the dimensions in order, I wonder if the very light torque + bend applied to the tuning pin suffice to compensate for some wear, up to some point of course. (then the pin is less straight in the hole.
When I feel the torque in the block raising I can feel it as if at first only a little torque exists at the bottom of the pin, then after a few tuning manipulations, the friction raise from the bottom of the pin to a higher part of it.in the end I can feel the grip on half of the pin, or may be 2/3.

Paper may add more friction than some oily wood, sure when poplar shims are used they fall in dust too, but the pin can be hammered.

If the block have really cracked layers, I dont believe it can be really repaired without gluing new wood dowels.

Isaac,I'm mean just micro cracks around the cylindrical outer wall of the hole of bush and hole's pinblock . I admit, and your assumption about of strong wood compression. I'm think so that (wood layers of a pinblock) can loose their a hitch gluing

Bravo,Isaac.
This axiom must be understood a tuner of piano

Some folks have mentioned some success with epoxy on cracked blocks. I don't know how nice that pin will feel afterwards since I normally try and scrub out residual glue powder with a gun brush and blow clean after reaming, before driving in a new pin.

The 1/2" delignit pinblock dowels work great if you prep them properly for installation. I stipple the outer surface with a sharp punch for better adhesion.
Normal dowels with the grain aligned in the direction of the pin length will not provide a long term good solution.

Some suppliers are selling broken up sets of pins now (dozen/half dozen ect..) so there really is no big financial set back not to be supplied with every size/length configuration for in field repairs. You can supply yourself with every combination possible (including blued and nickel plated) for about the cost of a full set of decent pins these days.

Emmery, I do think that so epoxy's glued and the frozen section of a pinblock will be greatly have the necessary friction between wood metal pins. However, what you are doing pre-cleaning this a holes after the epoxy's hardens"a gun brush" it is correct. Thus, when screwing or if a hammering of mallet a pin will not be badly as a pin out change. You can tuning this pin. It's will have a uniform frictions and will not be any problem for the technic

Max, you may have misunderstood what I wrote. I don't use epoxy as a repair for cracked pin blocks myself. I'm not 100% sure, but I think it was Del Fandrich who mentioned this repair option in another post a while back. I believe the pin is driven into the wet epoxy and then it gets twisted/broken free after it sets. Since I haven't used this process myself I can't comment on what kind of condition it leaves the pin in, for tuning afterwards.

The gun brush I use is a new .270 caliber bronze bristled brush or a worn out 30 cal. brush for oversized holes. I have it attached to a T handle. I will use the brush after drilling a pin hole or reaming one, just to loosen any glue residue, sawdust and glazing. Once its blown out with high pressure air you are left with nice clean wood contact on the pin that gets driven in.

Emmery,I'm sorry, I thought that we are talking about repairing cracks with epoxy block. What concerns the direct injection of epoxy into the hole, I say "No". If we pour epoxy into the hole and then put the pin back, it is glued a pin with wood hole of the block. I think that a tuning such a pin would be difficult to make

I read the message, "Emmery". His entire message confirms that the carboard is effective.I’m entirely sure.

Dear Alexandr I also hope that the message by Emmery is a good example for practical technicians of a piano. There they were able to see examples of his rehabilitation work with the piano (East Europe) to use that cardboard is really able to establish the loose pins. I can only add that the installation of corrugated board works perfectly. Dear technicians do not be afraid to use it in my own everyday practice

In some cases, I use a thick more 3mm corrugated shim