Hi List (yes, after a long, drawn-out debate, your parents decided to rename you "List." I'm sorry to have to be the one to break it to you....), I am finishing up a Renner back action retrofit, and when I got to the spring regulation stage, I got the idea to try the following: • Elevate the damper tray • Carpet-tape a fin to my cheapie HF tenth-of-a gram scale (I always knew that the scale was dying to sport a slick, aerodynamic dorsal fin) • Zero the scale • Slide the scale fin under each underlever for measurement -------------- next part -------------- A non-text attachment was scrubbed... Name: ScaleUnderleversJD.jpg Type: image/jpg Size: 32620 bytes Desc: not available URL: <http://ptg.org/pipermail/pianotech.php/attachments/20100727/a5c6214d/attachment-0002.jpg> -------------- next part -------------- The reading on the right is 24.2 grams (can't see the decimal point in the picture). I chose the fin height to lift the underlever about half the distance that the back of the key moves (I'm assuming that the key will engage the underlever at half of the keystroke), hopefully recreating the spring/weight force when the key is fully depressed (the spring strength increases as the underlever is raised). Anyone do it this way? Any problems or suggestions? On a related note, I wondered about the the joint in the Renner damper tray (between the tray and the back). Although the laminated beech looks to be extremely stable, the tongue and groove joint that joins the two halves of the tray looked like a potential weakness in the design. I took the offcut, and tested the joint: -------------- next part -------------- A non-text attachment was scrubbed... Name: DamperTray.JPG Type: image/jpg Size: 20742 bytes Desc: not available URL: <http://ptg.org/pipermail/pianotech.php/attachments/20100727/a5c6214d/attachment-0003.jpg> -------------- next part -------------- It broke quite easily with moderate hand pressure; I didn't even have to use any of my nonexistent super-powers. All kidding aside, it didn't require anything close to full adult strength to break it. Now, I know that the joint in the whole tray is much stronger due to its increased length and surface area, and also that the tray is not stressed very much in use. So, I'm not trying to suggest that this is a big problem or to criticize Renner. Still, it made me a bit uneasy. Has anyone had any problems with this joint, either recently, or in rebuilds you did in the past? Any comments about either issue welcomed, Joe DeFazio Pittsburgh
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