At 07:50 -0700 13/10/2010, Gene Nelson wrote: >...Mabye I am not getting the big picture and that is typical for me. >But - if the string height becomes lower toward the treble, it seems >that if the hammer line remains level there will be an issue with >key dip - it will deminish as the blow distance deminishes. One very big IF there. As I have mentioned in previous threads on the subject of hammer boring, the hammers should be bored so that when they are at rest the shanks are in a straight line parallel with the key bottom and the heads are all at the same distance (the 'blow') from the strike point on the respective unisons. The slope, if any, of the string from bridge to bridge towards the high treble needs also to taken into account to ensure that the hammer strikes the string at 90°. The blow, therefore, does _not_ diminish as you suggest if the hammers are properly bored, and I have never heard of any Steinway handbook that suggests that the blow should be anything but equal throughout the scale. I have just bored a set of hammers for a colleague who is replacing the heads on a very old Hamburg B. Going by his carefully checked measurements, the bore at note 21 needed to be 46.6mm, at note 52 49.3mm nad at note 88 40.6mm, this last measurement is 3.4mm shorter than it would have been (ie. 44mm) if the strings were horizontal, but he reported an increasing slope to 1.5° from note 69 to note 88. This is why it is impossible to get anything right with a set of "standard bore" hammers and why those of us who, besides wanting to do the job properly, prefer an easy life, order hammers unbored and to our specifications. Standard bore should be renamed Botcher Bore. >The question is do you regulate that way or do you try to keep dip >constant? If you keep it constant would it not be reasonable to have >a key level that was higher in the center than the ends? It follows from what I have written above that I keep the touch depth equal, the blow equal, the rest cushions of equal thickness, the shanks at rest an equal height above the rest cushions etc. To return to the question of the arched key-bottom: the last two Steinways I did, both from Hamburg in the 1970s, did have the key bottom arched almost exactly 1mm in the middle, whether by chance or design is no matter. In both cases, and in other cases, I level the keys so that the key tops are all the same height above the key bottom. This means, as I mentioned in my previous message, that every key will have an similar thickness of punchings at the key bed under the baize. If technician X likes to praise me for arching the keys, well and good, provided he knows why I did it, and ditto for the hawk-eyed diva with an eye for a curve. JD
This PTG archive page provided courtesy of Moy Piano Service, LLC