[pianotech] tightening balance hole was Bouncing Bostons

[John Delacour]

Those of you with memories that go back 5 months will remember a 
discussion (thread: Pully Keys) of a _serious_ balance hole case, 
which no amount of Elmers balsam or blue steam would have remedied.

The illustrated solution to this problem is shown here:

<http://pianomaker.co.uk/technical/pully_keys/>

JD