David Love wrote: > I run into this sort of situation frequently and I would like some opinions. > Steinway model S ca 1936. I am replacing hammers and shanks only. I use > Steinway hammers full taper, Abel shank 16.5 mm knuckle gives me the best > combination of regulation/downweight from which to work. The strike weight > is medium and consistent throughout. Key weight ratio is 5.0. When I > install the hammers, I will still want to take 2-5 grams off the downweight > throughout much of the piano (though it is somewhat erratic) to get a 52-48g > taper. Doing so does not compromise the upweight. The present front > weight of the keys allows me to add lead without exceeding the maximum > recommended front weight (according to Stanwood charts). But... the keys > already have a fair amount of lead grouped mostly toward the balance rail. > Though the front weight is not excessive, the keys themselves weigh a lot > because of the amount of lead in them (e.g. C16 = 163g , C40 = 144g, C64 = > 133g). I have the option of adding a small lead, or removing two or more > large leads from near the balance rail and replacing them with one large > lead out toward the front of the key. The latter will produce a more > conventional leading pattern--and involves a lot more work. > > My questions are: > > 1. Which one will produce a better feel? You are going to get a bit of differing answers on this, as to some degree its a bit subjective. More mass means increased inertia, (Paul I believe you have your physics just a bit mixed up,, either that or Ed McMorrow and at least one other major author on the subject matter is,,, Bennel is it ?? shoot my books are at the University). In any case more inertia can slow the action down in a very real sense... course there are optimals of speed as well as anything else.... so in the end you have a bit of leeway either way. > 2. Will the difference be significant? It can be quite noticable. Take a key without any leads sometime, (grand action, stack on) put say... 5 weights as close to the Balance rail as you can get them. Measure Down Weight and Up Weight. Note how the measurement behaves.... whether the weight starts going down and stops half way, or whether it goes smoothly all they way down (or up in the case of upweight). Now set enough leads out towards the end of the key til you have close to the same down weight as before (there will be a lot less lead) and do the same thing. You will probably note that you get smoother up and down weight measurements with the leads in the middle then out towards the end of the keys. This is inertia at work. Once a high interia piece of something gets moveing... it likes to stay moving. Now the down side of that is that when the key needs to start moving in the opposite direction there is a higher inertia that wants to prevent it from doing so. On the other hand to low interia results in a touch that can feel heavier towards the bottom of the key stroke then at the beggining, (as you shoulda noticed in taking the down / up weight measurements). The trade off then is smooth stroke vs speed. You want to find a happy medium. > 3. Do front weight parameters change with the overall length of the key: If the key ratio is the same in two different key lengths, then no (unless there is simply more weight in the front of one or the other key) i.e., is the allowable front weight greater for a model D than for a model if it is its not because of the length of the key in itself. > S, or there other factors The Key Ratio is, I think what you are after in this context... tho front weight as specified by David is a bit more involved > 4. What additional information will be helpful in making a quantifiable > decision? A bunch of things really... and its really interesting stuff... a fun journey that is well within the grasp of all field techs... a great alternative to the hardcore rebuilding trade. I would advise starting of trying to hold well withing the bounds of David Standwoods guide for maximum front weights, and try to create as smooth a key stroke as you can. As for balanceing your Strike Weights to achieve your desired Balance Weights, I will defer to David to advise you on that matter as all this is somewhat protected by his patents. Tho I will say that if you study his formulas and think on the matter you will understand better whatever advice is forthcomming > > > David Love > _________________________________________________________________ > Get your FREE download of MSN Explorer at http://explorer.msn.com -- Richard Brekne RPT, N.P.T.F. Bergen, Norway mailto:Richard.Brekne@grieg.uib.no
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