Actual piano question: Pin strength

[Roger Jolly]

Greetings Marcel,
                              The Rockwell test is used to check 
hardness.  May or may not be useful.   Hardness can be accompanied by 
brittleness, and may make a given material useless,in supporting torsional 
stresses.
There is a big difference between compression strength, verses tension 
strength.
I would love to see some figures, that include ductility, carbon content etc.
I have not see any real problems with either of the mentioned brands.   You 
can bet that all three brands have done their home work, with regards to 
overall strength.   And then had to make choices.

The diameter of the pin would have a big effect on the overall strength, to 
resist shearing.

Now the cat is amongst the pigeons.  <G>

Have a great day.

roger


t 08:36 AM 3/6/2003 -0500, you wrote:
>Hello Gordon,
>
>I have a friend in Toronto who had such a test made on tuning pins.
>It's called a Rockwell test. Rockwell is a steel strenght test. The
>results were not surprising. Fly brand came up first, then denro and
>Yamaha were kind of down, not to say the least. One thing we have to
>remember is that Asian piano builders rely on #1 metric tuning pins
>which are kind of small diameter. Add that to the softness of the
>stell they use and we get the problem you described. I find some
>bottom of the line Young Chang even worse for that feeling.
>
>Marcel Carey, RPT
>Sherbrooke, QC