You don't get more aftertouch just because the capstan is screwed up higher, you get more because the hammer is closer to the string and doesn't have to travel as far to get to let-off. If you have different string heights, same bore distance, different shank heights (to keep blow the same) then the aftertouch will not vary as the blow distances are uniform. I made the comment about bass/treble bore being the same based on your remark about it. Obviously if the shanks are the same height, the bore distances will vary (assuming its an overstrung bass). I'm not sure what you are talking about now. If the bass string heights are 1/4" higher than treble, then the bore will be 1/4" greater for the bass, the shanks will be on the same plane. If you bore the bass and treble the same (I have no idea why you would) then the bass shanks will be higher off the rest cushion. I thought that was what you were talking about. With the hammers closer to the rest cushion the hammer doesn't rebound as far below it's rest position and the jack can get under the knuckle sooner, thus better repetition. The only time I can see where it makes sense to not bore the hammers at string height - hammer flange center pin height, is if that distance creates a problem for the hammers getting under the pin block when you push the action in or out. I've seen this on some old Bechsteins recently. Measured bore distance would have been 2 3/16 for some sections in the treble. 1 15/16 was the maximum I could bore and not have a clearance problem. So I bored the set at 1 15/16 and adjusted the hammer/shank angle so that the hammer would be at 90 degrees to the string on impact. Since each section had a different string height, I had different angles on each section, different hammer lines and different shank heights off the rest rail. Because the blow distances were equal, there was no noticeable difference in the way each section regulated. That also seems to be the way the piano was set up originally. David Love ----- Original Message ----- From: "Richard Brekne" <Richard.Brekne@grieg.uib.no> To: "Pianotech" <pianotech@ptg.org> Sent: October 21, 2002 1:09 PM Subject: Re: key dip, dip in..... David Love wrote: > If you have different string heights in each section (like many older > Bechsteins, for example) then you will have different hammer line in each > section to make the blow distances equal. If the boring was done standard, > then you will have different shank heights in each section as well. > Different shank heights means capstans screwed up higher on some then others, and sets up different aftertouch. You end up haveing to give somewhere... either dip, aftertouch, or blow. Most pianos seem to have at least a couple mm variance in the treble sections, and few seem to echo this in their bore lengths. Actually, if you look closely at factory bore lengths, you wonder sometimes what and how much the fellow had to drink the night before :) A straight hammer line or one that gives at least the illusion of one, is going to reflect some of these differences, hence the +/- 0.xxx we see. I personally aggree that it is aftertouch that pianists most sense, and not a half mil of dip. So I aggree with Ed, and indeed what I was taught all those years ago by Yamaha guru Laroy himself... the aftertouch priority regulation. > I will admit I've never seen a piano where the bass was bored the same as > the tenor/treble. A shank farther off the rest cushion will not repeat so > well as the one set closer. Not sure what you mean... bass bored the same as tenor / treble.... but certainly I see bass bore lengths so that shank height is the same as in the treble, and I also see bass bores so that shank heights end up being just a bit higher... about the difference in string height. Why would the shank farther off the rest cushion cause a slowing in repetition ? I can see that one might end up having to have just a hair stronger rep springs in that situation, but I dont otherwise see any conection to rep speed. > David Love > Cheers RicB -- Richard Brekne RPT, N.P.T.F. UiB, Bergen, Norway mailto:rbrekne@broadpark.no http://home.broadpark.no/~rbrekne/ricmain.html _______________________________________________ pianotech list info: https://www.moypiano.com/resources/#archives
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