This is an amazingly helpful, detailed post showing great edication to quality. Thank you! Gordon --- A440A@aol.com wrote: > I posted: > >"This comes from hanging trial hammers in the > middle of the section and > > >moving the action in and out to find the best > contact point on the string." > > Alan writes: > >Moving the action in and out? > >I've seen curved hammer lines to accomodate the > dampers. What does that > >do to ideal strike points? > > (Hmm, I must apologize for not stipulating that I > was referring to grand > actions, the upright action must be raised and > lowered to analyze the same > question.) > > On a Steinway grand, the hammers are usually > hung 130 mm from the > center pin. So, it is a simple matter to have a set > of trial hammers, of > varying bore lengths, hung at this distance, at > exactly 90 degrees to their > shank. I use them find what bore distance allows > the hammer to meet the > string at 90 degrees. ( I do this with a small > square on the strings against > which the hammers, with their centerlines marked, > are compared when they > touch the string). Then I bore the set and install > the end hammers in each > section at 130 mm. I put the action in the piano > and listen to changes as > the action moves in or out. If it improves the > sound of a section to pull > the action out 2 mm, I simply hang the hammers in > that section at 132 mm. > Sometimes I find that the middle of a section needs > to be farther out than > the ends, so I make a note of this and hang by the > following procedure: > In the upper sections, I put a hammer in the > middle of the section and > listen as it is moved in or out. This is where I > find that hammer lines can > produce better sound when curved within a section, > but it usually turns out > that the curve is gradual within any given section. > Separate sections under > the V-bar usually have their own distinctive "best" > hanging distance. > These curved hammer lines are not easily > replicated on jigs with straight > edges, so I usually have one or two hammers within > the section that are > indexed to the optimum contact spot, and then hang > the hammers in straight > lines between them. At some point, the time it takes > to refine the contact > points to the last 1/2 mm is not worth it. Hammers > can be finely adjusted to > these tolerances with a little heat and a vertical > bend in the shank, if > necessary. Even a very slight asymmetry in filing > can move contact back or > forth, so I just hang straight between guides that > are perhaps 10 hammers > apart. > I also begin a replacement job with the hammer > shanks all traveling > straight up and down, as measured by a square > sitting on the whippen rail. I > space the shanks to begin their arc from directly > over the whippen flange > screw and with equal distance between them at the > knuckle. This provides a > beginning alignment "framework" so that when > decisions have to be made, I > know where I can safely depart from "ideal". > I often find that grands require the bass > hammers to be moved leftward, > and the middle section must be spaced to the right > if I am to have all the > top end directly under the strings and directly over > the whippen. By > starting off with everything straight, I know how to > split the difference so > that nobody is way off center,(which would require > excessive spacing of > whippens, which leads to problems if the capstans > are not perfectly aligned, > and the same goes for the let-off buttons). > I hate to burn shanks,(though I do), so I really > want to know that they > are traveling straight before the hammers go on > them. Also, especially in > regard to Steinways, once I know that they are > traveling straight, I know > that I can space them with two equal-sized shims of > brown paper tape used on > the diagonal and not change the traveling. This is, > ultimately, a time saver > when the greatest degree of perfection is the goal. > > Sometimes it helps the speed of Steinway > regulation to combine the > spacing and traveling, ie, if you know the hammer > needs to strike farther to > the left, and it is traveling to the right, a simple > spacing paper on the > right side of the flange will cure both at once. > And, if it is traveling > right, and hits the string just right, the Steinway > flange allows one to shim > just the front right corner, so that the shank > travels more to the left, but > the flange is swung to the right, keeping the > contact correct, while making > the hammer travel straight up. > Regards, > Ed Foote RPT > _______________________________________________ > pianotech list info: https://www.moypiano.com/resources/#archives __________________________________________________ Do you Yahoo!? New DSL Internet Access from SBC & Yahoo! http://sbc.yahoo.com
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