For anyone that is interested I did find a solution to this: I needed to measure the height of each key end from the keybed at rest and at full key dip - used a 200g weight to get consistent key dip. (the action is accurately regulated - dip and height are very accurate) After charting this on spread sheet the intent of the mfgr began to emerge into my brain. Key ends all travel (vertical distance) different from each other slightly. Longer keys travel less than shorter ones and sharps travel more than naturals. (on this piano anyway) The key length increases about 8mm from note #1 through #65. As the new felt under the keys on the back action rail was consistently the same height from the key bed this meant that the keys were as well. The bass natural key ends travel (vertical distance) 1.0mm less than the upper tenor naturals and the bass sharp key ends 1.0mm less than the upper tenor sharps - evenly tapered. The sharps full travel (vertical distance) at the key end is generally 2mm greater than key dip. The naturals is 1mm greater than key dip. As a group, the sharps and naturals (measured at the key ends) at full dip are on a straight line that is higher in the upper tenor by 1.0mm than the bass. I shimmed all key ends so that the naturals were parallel to the keybed as well as the sharps but sharps are 2.0 mm lower. After I build the back action it is my sincere hope that this is really a solution and the new damper timing will feel and look even. Gene ----- Original Message ----- From: Gene Nelson To: pianotech at ptg.org Sent: Sunday, May 31, 2009 3:02 PM Subject: key ends and damper timing Hello list, After leveling keys and setting dip accurately and doing some regulation I went to the key ends to begin the process of taking location marks for a new back action. Striped off the old key end felt and found that the key ends of the sharps are less in elevation from the key bed than the naturals. Did not notice this before striping off the key end felt but was not really paying attention and the felt was badly worn anyway. At full key dip they become much closer to equal elevation from the key bed - that is in the bass. As the keys get shorter in the tenor and high tenor sections the key ends are much closer together at rest and the sharp will lift higher in elevation than the naturals. The factory must have done this?? The question is - what is the best option for damper timing. 1: I could fully dip all keys and trim the key ends so that they are all the same elevation from the keyed. This will allow a nice unstop rail adjustment. The down side is that the damper lift levers will have different lost motion with the key ends. Appears to me that if the sharps pick up the lift lever slightly different than the naturals it may not be so noticeable if it was consistent. 2: I could leave it the way it is and the damper levers will generally get picked up at around half key travel but sharps and naturals at full key dip will have their dampers at different elevations making the unstop rail higher than desired. Someone at the factory had something in mind and I am missing it. Any help would be appreciated. Gene -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech.php/attachments/20090604/ff0b77c1/attachment-0001.htm> -------------- next part -------------- A non-text attachment was scrubbed... Name: keyends uneven.jpg Type: image/jpeg Size: 52304 bytes Desc: not available URL: <http://ptg.org/pipermail/pianotech.php/attachments/20090604/ff0b77c1/attachment-0001.jpg>
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