Hello List, I had the opportunity today to make some little test on a recent 1 year old Steinway B, that is fitted with double large "concert casters". 1? The casters oriented toward the front of the piano , the tone was less full and less strong. - I asked somebody to confirm that, and I used the VT 100 in Spectrum mode to look at the peaks. Doing the experiment while playing a definitive less strong 1st partial with the casters in front. 2? the case was apparently coming from differences in bedding (slightly less pressure on the keyframe, so I used a dial gauge mounted in reverse direction (on a little wood support as the idea have been given us by Ron Overs), and looked at it on the break glide bolt while passing the casters from front to back. I have seen a repeatable 1/10 gradation change of the dial gauge . That mean that the caster oriented front I had slightly less pressure on the little bedding screws . Time was missing for more "scientific" experimentations, but the change in bedding is evident. Then I made the same experiment but plucking on strings (for 2 notes only, I'll do better later). Apparently, the spectrum analysis of the VT 100 shows also a slightly stronger level for the 1st partial with the rollers oriented towards the tail. That should be interesting to investigate further, on pianos with less large rollers. If the change is as noticeable, that should be one of the first thing to investigate before bedding the keyframe, and that should also be an advisable method to orient the casters toward the inside of a piano in case lack of pressure in the middle seem evident, and you have no time to open the piano (on the opposite, orienting the rollers externally should lessen the pressure. Indeed that may depend of the piano and the size of the casters. I have been amazed years after year on how often it was necessary to touch up the bedding. Seem that I missed one basic point there (never too late !) Greetings. Horace of course the paper strip bedding is not employed actually, on tricky to bed keyframe like some 4 screws Renner hard wood stacks, or if the Stack is so old the balance rail wood is very rigid like on some 1900 .. S&S, the method to get a minimum contact with the dial gauge, then add an even pressure is a must. I bed from the middle, so the end are always done last, nowadays the pressure on the right/left screws is not as clearly defined as on the center, the tone give good information's there also. BTW the best method for those stacks that don't "knock " easily is to push 2 or 3 fingers on the key capsule while my hand is locked under the pin block, that way I have a lot of force to push and a firm reference. At the same moment with 2 fingers I lift (strongly) the bedding screws, it is then possible to hear and test a somewhat soft knock under the glide bolt (produced by the fingers pressure impulse on the capsule of the key), and check the amount of pressure necessary to lift the rail. (one of the Bechstein original factory method). The method tend to compress a tad the balance punching, test for evenness and add a very thin 'silk paper punching if necessary. Best Regards to all. Isaac OLEG > -----Message d'origine----- > De : Horace Greeley [mailto:hgreeley@stanford.edu] > Envoye : vendredi 9 janvier 2004 05:39 > A : oleg-i@noos.fr; College and University Technicians > Objet : RE: Steinway casters orientation > > > > Isaac, > > At 03:20 PM 1/8/2004, you wrote: > >Thanks, John, indeed that make sense, I need to check that on less > >large instruments as well (one Grotrian particularly is > strange when > >it comes to stability of the key bedding in the basses. > > > When bedding the keyframe, try working from the second stud > from the base, > rather than from the end. Then when the others are set, go > back and do the > bass. > > Also, on a number of instruments, the keyframe has a tendency to > "float". Stated differently, they are exceptionally > sensitive to humidity > changes. If/as I notice this kind of behavior, I tend to > set the bedding a > bit more tightly than I otherwise might. > > Along the same lines, many more modern instruments do not > seem to want to > get properly bedded unless this is done with the keys and stack in > place. I do not think that many people still try to use the > newspaper-under-the-balance rail approach anymore. It > really is rather > useless when the keyframes are so flexible. > > Hope this is of some value. > > Best. > > Horace > > > > >But then, one may consider that the fixture of the legs is not as > >rigid, and can be moving the keybed slightly ? it may depend of the > >piano, but then the same idea apply . > > > >I have seen a sketch showing the roller oriented toward the tail of > >the piano after a S&S training in a workshop, but no one cared to > >answer me on that point (as I was not invited to the training, see > >;>( ! > > > >Are American grand's usually sold without rollers ? > > > >Best Regards. > > > >Isaac > > > > > -----Message d'origine----- > > > De : caut-bounces@ptg.org > [mailto:caut-bounces@ptg.org]De la part de > > > John Minor > > > Envoye : jeudi 8 janvier 2004 22:57 > > > A : College and University Technicians > > > Objet : Steinway casters orientation > > > > > > > > > > > > I was told that the large european casters should be set > > > perpendicular to > > > the keyboard to prevent splaying of the 2 front legs which > > > could make the > > > keybed drop slightly in the middle and cause slight > > > regulation problems > > > there. Sounds plausible to me. > > > > > > John Minor > > > University of Illinois > > > > > > > > > > > > > > > _______________________________________________ > > > caut list info: https://www.moypiano.com/resources/#archives > > > > > > >_______________________________________________ > >caut list info: https://www.moypiano.com/resources/#archives > > >
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