Pinblock too low

[Mike and Jane Spalding]

List,

Today I was asked to examine a "rebuilt" piano and figure out why it plays so poorly.  Knabe small grand from mid-1920's.  It was obvious just sitting at the kyboard an playing a little, that the damper timing was way uneven, and drop was way low.  Thought the solution would be failry straightforward.  Then I pulled the action, which did not slide out easily, and saw the pinblock hanging 1/4" below the stretcher, and the furrows ploughed (plowed?) by the drop screws.  OK, now we know why the last guy didn't regulate the drop.  Obviously got to make some room to raise the drop screws.  Shanks are original, so I might gain something by bolstering knuckles, but probably not enough.  I could go in there with a disk sander and grind some off the bottom of the pinblock, but I'd prefer not to inflict the noise and mess on the customer's living room.  Anyone else ever faced this situation, and found a neat (i.e. reasonably clean and quiet) solution?

thanks 

Mike Spalding, RPT