I think the main reason this idea never really got established is that the are too unstable. Actually on many uprights there is a similiar configuration, tho the screw is meant to be down tight. The purpose of this in modern uprights is really more to make it easier to select the best size pin, as one only needs to take regard to the bushings. One problem with these is that some "techs" seem to use this "adjustablity" of these to solve problems relating to tight centers. Of course this doesnt work really well and more often then not causes more problems then it solves. We gotta just face it... the good 'ol fashioned center pin in bushings and tight in a hole for the part thats going to move is still the best anyone has come up with. Mini ball bearings and the like are just going to be too expensive and would probably have all kinds of problems with lubrication and dirt and all.... nahhh... better to keep things simple in this case... and me thinks that also means living with a non adjustable configuration. Its not like folks havent been trying for years and years to come up with anything better... or what ? Farrell wrote: > I have been doing a bit of work on an old square grand. The hammer flanges > are long and are split horizontally through the flange center. There is a > screw that can be turned to tighten/ loosen the bushing fit to the center > pin. I'm sure many or most of you have seen this. This is so cool. Is there > any significant disadvantage to such a design? I can see that with the > flange on the modern grand, size/space would limit the possibilities. Seems > like it would be worth some level of redesign to be able to adjust the > friction in this critical action center with the turn of a screw. > > Terry Farrell -- Richard Brekne RPT, N.P.T.F. Bergen, Norway mailto:rbrekne@broadpark.no
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