visegrip "voicing"

[Duplexdan@AOL.COM]

Dave,

I have a Sojin Grand piano with very hard hammers. Even the heaviest of 
voicing tools hardly penetrates the sruface. I have successfully and 
laboriously needled the hammer acorss the shoulders through the crown and 
achieved a very successful result. My question is,

IS THIS GOING TO BE TEMPORARY ? or would breaking u the whole hammer with 
vise grips be advised. If your experience allows you to comment on this 
problem I would be most grateful for your comments.

Dan Franklin, RPT Singing Tone