I visited workshop of Beethoven Pianos where I'm managing at moment. I realize how complicated and time consuming works to rebuilding soundboard... Also breast takingly beautiful.
the first, taking a old soundboard, carefully and gently from the rim.
You trace the shape and location of the bridge where the strings will be laid on.
Then place ribs to support soundboard.
Then install soundboard and pin-block
Tuning pins hold strings, when they are not able to stay (slipping and does not hold in tune) need bigger pins. (Size 0-5 are available) after few change you are not able to change.
So many process and precise work!
At Beethoven Piano's work shop