Of course hammer shanks have been burned almost as long as there have been pianos. Mostly, to my knowledge, it has been done to correct alignment of the hammers as they lie in a straight line. Burning shanks to center a raised hammer tail between its neighbors, at rest, is quite another thing. I'll take your work for this being a long standing European factory procedure. On the surface, it makes perfect sense to do so. It would seem reasonable to think that centering the hammer tail of a raised hammer between its neighbors at rest, would only serve to refines a perfectly vertically oriented hammer with no cant. However, centering the tip of the hammer tail between neighboring heads does, in fact, result in a slight cant angle; it's unavoidable. Maybe it's not enough to matter, but that is not quite what I am talking about. Maybe what you are talking about is not a different means to the same end, after all. This may be where the difference lies. For me, it's not a matter of centering the tip of the hammer tail between the neighboring heads; it is to position the hammers such that there is equal clearance on both sides, to the extent that this is possible. On one side it is the tip of the tail that comes closest to interference; on the other side the greatest risk of interference is closer to where the shank enters the hammer molding. I prefer a larger cant angle for the purpose of getting closer to equal clearance on both sides, not centering the tip of the tail. In fact the tip is deliberately off center a bit, to relieve the closer clearance problem on the opposite side. Any significant cant angle necessitates one of two things, an action scale offset from the strike point scale in an amount anticipating the cant angles of the hammers, or a misalignment of action parts to get the hammers centered back under the strings despite the offset of the cant angle in those instruments where the strike point scale exactly matches the action scale. Frank Emerson
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