<html> <body> Andreas - My first thought was to suggest that you try impersonating a German engineer, and come up with a lengthy, un-hyphenated word that describes exactly what it is and what it does.  Something like: uprighthammershankstrikedistancedifferentialanglunginn.  I thought a bit more about it and concluded that, it is a spec that would probably be infrequently applied by either general technician (unless one was redesigning an action), but, even if I'm wrong about that, its applicability to action response presupposes that the string plane itself is perpendicular, both by design and in situ  (ie. is the floor level?).  In theory, that angle, or those distances could be altered to have no effect on repetition and touch or significant effect.  In fact, it seems as though it might be possible to achieve a range of touch regulation by altering the  caster heights, front to back.  The angle, in relation to true perpendicular would be relevant, and worthy of a name, like upright hammershank offset angle, or something. I can also envision a relatively simple tool that could provide a direct angle reading.  Good thing we have springs! Looking forward to the book. David Skolnik At 11:29 PM 11/28/2006, Andrea Reisberg wrote: <blockquote type=cite class=cite cite="">Fellow colleagues, The second term is only applicable in uprights. When the hammer touches the strings, there’s a small difference between the distance from the strings to the shank, just beneath the hammerhead, and the distance from the strings to the shank down at the butt. Directly translated from Norwegian to English it would be called Hammer Fall Angle. Ironically, although it’s called an angle it’s expressed in mm instead of degrees since it’s the difference between two distances. What is the English name?</blockquote>and: <blockquote type=cite class=cite cite="">It is rather the angle between the shaft and the strings at impact. This has to do with balance; if only gravity were the acting force, a relatively heavy bass hammer balancing against a light butt and back stop wouldn’t be as inclined to returning to its starting position as a light treble hammer balancing against the butt and back stop. This measurement is something you would check when reinstalling the action if you have removed the keybed and the action bracket bolts during a rebuild. If this angle or measurement is too small, repetition will be slow or lost, and if it is too big the touch will be very heavy. </blockquote> </body> </html>