I'm no expert on piano designs, but you could likely tell pretty clearly by using a nice 4-foot straight edge and laying it across the keybed in the back, in the middle, and across the front, and then also from front to back (as you apparently did) in the middle and at the two ends. I should think that if it were designed, the curve/bow/whatever should be regular, i.e. the whole front would be curved down, or something like that. I'll bet that either the front of your keybed has sagged in the middle, or the middle portion (front to back and side to side) has bowed up. I can't imagine anyone designing a sag in the front center, or a bump in the middle! Sounds like a good thing you have a flexible keyframe! Don't bother wasting time with bench regulation! I like to do my rough regulation on the bench, so I always take my key leveling stick and check out the keybed - just to make sure it is pretty planar. That way I know I can come close on the bench. I find that if the keybed is real planar, and you have a real flat planar regulating table (not easy to get without making sure it is planar), I can come real close to the final regulation on the bench. If the keybed is all warped, forget the bench - maybe forget the piano! Terry Farrell Piano Tuning & Service Tampa, Florida mfarrel2@tampabay.rr.com ----- Original Message ----- From: "Larry J Messerly" <prescottpiano@juno.com> To: <pianotech@ptg.org> Sent: Sunday, February 18, 2001 2:19 PM Subject: Crown in Key Bed > I am presently working on a Kranich and Bach that appears to have a > one-eitghth inch crown in the key bed. (Using a straight edge held down > at the back of the key bed, it is 1/4 inch off the keybed at the front.) > > Is this the way the piano was designed or is this damage of some kind? > > The key frame is VERY flexible in that when it is removed, the front rail > can easily wave in the breeze. > > Larry Messerly, RPT > Prescott, AZ >
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