<!doctype html public "-//w3c//dtd html 4.0 transitional//en"> <html>   A440A@aol.com wrote: <blockquote TYPE=CITE>Bill writes: >I agree that a good healthy blow will put the frame under pressure, >but if the BR doesn't have anywhere to go (because the glides are >contacting the bed),   I have been wondering when somebody is going to mention the entrainment of the keybed?  Once the glides are in contact, the action cannot move, UNLESS the keybed is not absolutely rigid.</blockquote> Hmmm... I wonder about this. I know it makes sense.... and indeed that very assumption has been the basis of how I've approached bedding the keyframe for years. Yet the last few days has demonstrated that putting the key frame under stress by turning the bolts down a bit more, significantly afftect the power of the action and quite clearly decreases the amount of movement in neighboring hammers and shanks at fff levels of play.  If it was the keybed I suppose I would expect any instability to be most apparent in the center of the keyboard, but I dont. Its always the bass and tenor regions that have given me most trouble... especially the bass. I guess that the added stress of the bolts being turned down a bit just makes the whole frame a bit stiffer, perhaps causeing the back rail to strain up against the dags contributes to this ??. But I dont really see how the increased stress beyond solid contact by the glide bolts is doing what it seems to be doing.   <blockquote TYPE=CITE> But we know the keybed isn't.  This is easily seen by depressing the pedals under a very lightly bedded set of glides and observing them to lose contact with the keybed.    So,  the extra power and tone being ascribed to heavier loading on the glide buttons may possibly be a function of preload on the keybed?</blockquote> Hmmm... maybe...at least in part. <blockquote TYPE=CITE>And the observed differences between makes of pianos may be more due to the differences between keybed strength than the flexibility of the balance rails?? Wondering, Ed Foote RPT <a href="https://www.moypiano.com/resources/#archives"></a> </blockquote> FWIW, I did the other Yamaha today... a C7, and one of our students came into get ready for a performance and sat down to play whereby she immediatly smiled up to me and said "AH.... there's some springyness to the piano now... what did you do ?"... I asked her if she was certain it wasnt too much and she played a bit and said it was just perfect. Rougly, they were a 3rd of a turn backed off from loosening the front rails grip on a thin strip of paper and evened. All this is a bit new to me, so I'm having great fun reading Bills, Rogers, and others thoughts on the matter. Clearly theres more to it then just gettting the glidebolts to all contact the keybed. Cheers RicB -- Richard Brekne RPT, N.P.T.F. UiB, Bergen, Norway <A HREF="mailto:rbrekne@broadpark.no">mailto:rbrekne@broadpark.no</A> <A HREF="http://home.broadpark.no/~rbrekne/ricmain.html">http://home.broadpark.no/~rbrekne/ricmain.html</A> <A HREF="http://www.hf.uib.no/grieg/personer/cv_RB.html">http://www.hf.uib.no/grieg/personer/cv_RB.html</A>  </html>