eleven tonnes of pressure on a piano to tune it. You need to see the way a piano tuner tunes each string to realize the kind of pressure he needs to exert on each string till it sounds exactly the way it is supposed to. The strings cannot be loose - they have to be taut and there are degrees of that tautness...
Each note has a trichord, i.e., three strings each. The tuner mutes the two outer strings so that only the middle one is free to vibrate. After he tunes this to the exact pitch, he tunes the outer strings to the one in the centre. This is only one part of the tuning process - it is a long and tedious process and the tuner goes on and on till he is finally satisfied. It is only then that the pianist can produce the most heavenly music.
Our lives too are tuned by the Great Tuner. So often we veritably quail under the hammer, we wonder when the pain will stop, we pray for the end of the hammering and tuning....but the Great Tuner knows when to stop. He wants the perfect pitch, the perfect temperament and the perfect overtones and harmonics.