<html> <body> Michael, The "tracks" you see are common in Kawai hammers which have been made very damp.  The marks themselves are made by the automatic pre-needling machine which Kawai uses to soften up the shoulders.  The machine needles both the front and the back sides, and the hammers are later (or are supposed to be) filed in the voicing department, so the  marks do not show. I have seen some hammers were the tracks show from lack of filing in the factory, and also some which came to a very humid place (or were steamed or treated with alcohol/water or something like that) where the needle holes reappear.  If the marks only show on the front side, this could indicate a, how shall I say it, 'less than artfully done' steaming of the hammers. The hammers are not soft sounding when they come out of this needling machine, because it doesn't go up to the tip, and it doesn't needle higher than note 60 (or somewhere near 60 - could be up to 64).  So the soft tone you and your customer have heard is not related to the needle marks, but the fact that these needle marks show and the tone is very soft makes me think that something else has happened. As long as the hammers have not been needled or steamed or wet on the very tip, it should be possible to file them some to get the tone back.  Use 600 grit paper or higher, and use a lot of speed and pressure to file up and over the hammers.  Try supporting the mid-treble hammers and gang-filing them this way, and see if they don't come back. For those who want more information on Kawai's voicing methods, please try to catch one of my seminars - I'll be doing one in Kansas City this Saturday and in Tyler, TX on Monday.  I'll be in at the Texas State and North Carolina seminars also, but not teaching voicing this time. Don Mannino RPT Kawai America (which, for those who don't know, does not sell or support the Boston pianos) </body> </html>