I have been taking some time to slow down and fuss with a couple of grand pianos in our university collection. In working on the bench with these actions, I have been frustrated to some degree with the apparent inconsistency I have been dealing with from note to note as I have chased some kind of uniformity in the regulation.
I am now working in the piano, and have for this project abandoned the use of a weight on the keys to determine consistency of key dip and aftertouch. I am finding the experience much more agreeable. The pianos in question are a 1977 Mason & Hamlin CC and a 1981 Baldwin L.
I am starting by confirming (and adjusting, if necessary) key height and key dip. I then dial in the hammer blow to a spec that emerges as workable in the process. I really don't want to see anything less than 46mm. (I'm accustomed to using .045" as my aftertouch spec, but on the Baldwin I've reduced it to .036 to achieve my desired hammer blow.) I then am refining the let-off so as to achieve what has been described in another thread here as ghosting - having the note sound softly when the key is played from a point where the jack has met the let-off button and the repetition lever surface has met the drop screw. I'm not looking for something ridiculously close in terms of let-off, but I don't want to have to be really vigorous to get a sound either.
Once these adjustments have been completed, I insert a let-off gauge under the key and see what I've got. I don't want let-off to precede contact, nor do I want to press particularly hard to move the note through let-off.
There is usually some fudging to be done, but I'm surprised at how much difference a little change can make. Both actions have Crescendo punching at the front rail, so I've got a pretty steady point of reference. I don't mind leeway of .005" in dip, but I don't want to see much more than that. Again, I'm working with finger pressure rather than a fixed weight, so I suppose that is giving me a bit of leeway as well. A bit of fudging can be done with let-off, but not much if I want the ghosting to have any kind of consistency. The hammer line is also negotiable, to the degree that nothing is allowed to be obviously out of whack. A little here goes a long way!
To my delight, I have not needed to accept much variation in how let-off feels at the front of the key with the gauge in place. There is a little, but once the gauge is removed, I am imagining that the difference in final tactile sensation is not going to be discernible by the pianist.
I finished working through the Mason & Hamlin last Wednesday, and got halfway through the Baldwin today. I really wonder if some of our other pianos are going to be as cooperative.
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Floyd Gadd
Regina SK
306-502-9103
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