George, Been reading back and forth some of these posts and get the feeling that as interested as you are in finding out how the instrument ticks, you'd be best served by getting ahold of your local RPT and having him look over your instrument, explaining things to you as he goes. You obviously have a lot of good questions for him and are capable of understanding the explainations as they come. Such a look over doesnt cost you much in terms of dollars, and would be worth those monies just from the instructional value such a visit would provide you. Owning a piano and starting to enter into the piano technician world is a route some of the finest technicians around have taken. But I think most of them have taken every opportunity to draw on as many resources for knowledge as are available. Hands on attention is the best in this kind of example, as you can have things demonstrated to you right there and then. The thing is... unless there is something structurally wrong somewhere, then some basic regulated condtions should result in a pretty reasonble action. 10 mm key dip, 46 mm blow distance, 2 mm letoff, 4mm drop. If when these are at or close to these specs something else looks waaaay out of whack.. then most probably something is wrong and you need to identify what exactly that is. It's a bit difficult to troublshoot an action from afar even with as much relavant information... grin.. heck sometimes its difficult to troubleshoot even when you are right on top of them. It would be neat to read your commments that result from such a look over as well. In the meantime, get a hold of Reblitz's book on piano technique. Cheers RicB George Whitty wrote: > After a long, careful examination of my piano (and my assumptions > about my piano), I've come to the conclusion that my hammers have been > filed several times. They're actually faceted, some in a fairly > lumpy, asymmetrical way, and looking really closely I can see and feel > two distinct rounds of filing, with possibly more; This is probably > where I'm losing most of that 3/16". I'm not in any position to > replace the hammers in this piano for now; that one's WELL beyond my > scope, so I'm looking for the best compromise. It occurs to me that > by shimming with a couple 1/16" washers beneath each of the 8 support > posts on the upper structure of the action (thus raising the hammers > 1/8") , then turning up the capstans and adjusting the backchecks > (these were going to need a regulation anyway), I could at least > preserve more of the correct geometry between the wippens and the > hammers than I would by simply screwing up the capstans until the > hammer travel is 1 3/4" but the hammer shanks are sitting way above > the hammer rests. The disadvantage of this approach is that I have to > crank the capstans even higher (or, as Barbara suggested, fill out the > wippen cushions more) to raise the hammers than I would if I left the > upper action where it is, thus taking advantage of the leverage (in > which lifting the wippen a little raises the hammer a lot). Has > anyone done anything like this? Is it just a terrible idea, or a > workable kluge until I can pay someone to replace all the hammers one > day? > > Thanks again, > George > > >> Hi, Mike: >> >> Thanks for the reply; I raised the capstan on my middle C to get the >> hammer 1 3/4" from the bottom of the string and took some measurements >> (didn't have time to do more keys today). Here's what I end up >> with: from >> the cushion to the shank is 5/16", the hammer bore is 1 31/32", and the >> distance from the hammer to the bottom of the strings is now 1 3/4". >> I took >> a look at a couple pianos today, a Steinway and a Yamaha, and their >> hammer >> shanks sit a very neat 1/8" above their cushions the entire length of >> the >> keyboard. Thus, doing the math, it seems that to achieve that in my >> piano, >> middle C's cushion should sit 1 31/32 + 1 3/4 + 1/8 + half the >> diameter of >> the hammer shank below the strings; unfortunately that 1/8" in my >> piano is >> a pretty consistent 5/16" or so, which makes me wonder if the whole >> keybed >> is somehow sitting 3/16" too low in my instrument. For those still >> bearing >> with me, I have a couple questions based on this information: >> >> 1. I notice that, while there's a good deal of resistance trying to >> push >> the hammer down to the cushion with the jack still under the knuckle, >> it'll >> go right down easily with the jack tripped. Is the cushion there >> only to >> catch the key if it rebounds too fast for the jack to get back under the >> knuckle, in which case I think my keys work fine even with the 5/16" >> gap? >> >> 2. Could someone enlighten me a bit more as to how to determine >> whether my >> hammers have been filed? Feeling around the edges of some of them, I >> now >> notice a little very slight ridge, a little angle as though some felt >> had >> been removed (the little ridge sits at about 9:30 and 2:30 on the >> hammer) >> they're definitely not just one totally smooth arc. I'm just not sure >> whether this is something done at the factory as a way of voicing the >> things >> or something. In any case, I think they'd look more out of round if >> there >> was 3/16" missing off the tops. >> >> 3. Is 1 31/32" a typical measurement for a middle C hammer bore, or >> does a >> "typical measurement" even exist? Is there somewhere that I might >> find out >> what this measurement SHOULD be for my piano? >> >> Thanks again to everyone helping me out with this intriguing problem.. >> >> George Whitty >> >> >>> Hi George, >>> >>> As Ric B. mentioned, something does not add up, literally, if the >>> shanks >>> are 1/2" off the cushion when the blow distance is 1 3/4". The >>> couple of >>> Hardmans that I've seen / worked on have regulated to fairly >>> conventional >>> dimensions. Picture the virtical distance from the rest cushion on the >>> wippen up to the strings. It wil be subdivided into 1) clearance to >>> shank >>> at rest, 2) hammer bore length (plus 1/2 shank diameter), and 3) hammer >>> blow distance. If 1) and/or 3) are larger than they should be, >>> then 2) is >>> smaller than it should be, either by design or through wear. Let us >>> know >>> what the bore distance is, for several hammers from bass to high >>> treble. >>> Also, take a look at the string grooves - how deep and long are >>> they, and >>> are they perpendicular to the molding ? >>> >>> Mike >> > > _______________________________________________ > pianotech list info: https://www.moypiano.com/resources/#archives >
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