We had the Long sisters Duo (great artists, don't miss them if you have the opportunity) here at TAMIU. During the course of their practice and the pre-concert tuning (done minutes before) some clicking developed in the hammers. I held adjacent notes down tight to eliminate slapping of the front rail. No joy. I put a finger over the damper and softened the upstop. That did seem to make a little difference. I checked, the rail is in place with plenty of felt apparent. I've had to reglue a few dampers including one after their practice so I'm suspecting the hammer-shank glue joint. Would this be a candidate for a little vinegar to reactivate the glue and tighten the joint? Or would it be preferable to simply remove the worst hammers, knurl the shank and re-glue? Andrew Anderson On Oct 6, 2008, at 2:30 PM, Richard Brekne wrote: > Greetings: > > > It's only logical that weight and distance ratios are related. You > can't change the weight ratio without creating the need to alter > regulation specs. While problem actions we're talking about that > have excess lead have, by definition, a mismatch between ratio and > hammer or strike weights, they also generally regulate with too > shallow key dip (<10 mm), at least by modern standards. Changing > the capstan or knuckle position to improve the ratio to strike > weight relationship will entail increasing the dip but that's > usually a good thing, or at least a perfectly acceptable thing. If > you want the action to regulate by older standards with shallower > key dip you will need to use very light hammers to go with a higher > action ratio (or compromise the blow distance). > > One thing that would be nice would be to establish the relationship > between the Stanwood weight ratio and the distance ratio (since they > don't currently match) so that regulation specs could be targeted > using weight ratio as the standard. However, since both numbers are > easy to calculate it doesn't present that much of a problem. > I'm not sure all this is all that accurate. One has to remember that > Stanwoods weight ratio is all in all an entirely different puppy > then the distance ratio as given by for example Ron Overs on his > website. Stanwood does two things that are not really compatible > with the distance ratio and can explain why the SWR can be the same > for two actions of different distance ratio. Number one, he throws > out the individual ratios of the top two levers in the action and > combines them into one quantity. Then this quantity is never really > used directly in his formula but is rather factored out to arrive at > his equation of balance ratio. (see my article on dissecting his > equation from a couple three years back in the Journal) Secondly... > his equation is that of the ratio of the SW to that of the combined > weight of BW + FW - WW where WW is the whippens radius weight times > the key ratio. It is not a direct ratio such as the distance ratio > which is the ratio of hammer movement to that of the key movement. > > It is clear that one can achieve identical distance ratios for the > upper two arms using various combinations of the individual arms. > Choice of individual arm lengths affects the speed of each of the > parts in each individual arm and the speed of the individual arms > themselves. This illustrates part of the difficulty in attempting a > translation from one type of ratio to the other. The end balance > weight ratio... or SW ratio as Stanwood has termed it is not > porportional to either a standard distance ratio or any given speed > ratio. > > The only relationship that does exist without further ado is that if > one increases or decreases any given action ratio through some or > another manipulation, one will indeed alter all other action ratio > measurements in the same direction. That is to say if you increase > the SW ratio, then you will increase the distance ratio and the > speed ratio as well. How much in each case is a bit more complicated. > > Another thing,... a change in the SW ratio by no means necessarily > implies a significant change in action regulation specs. One can > alter the SW ratio quite a bit and end up requiring no more then a > couple mm change in blow distance to achieve same aftertouch for > same key dip and same letoff/drop. > > Cheers > RicB >
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