The patient: Kawai 601M 42" console, 1989 (US-made), clean, and generally in good shape. Moved several times. Music desk missing; replaced by woodworker. Symptoms: Chromatic scale from middle C up plays fine. From middle C down, dip is shallow, even preventing escapement. A2 hammer also hits G#2 string. After opening the case, I notice that all the bass dampers are offset towards the bass side of the piano by a few mm. The hammers are shifted left as well. Eventually I discover that the leftmost action bracket is much lower than the rest (see pictures). Usually the open "U" is wedged tight against the support bolt coming out horizontally from the plate. This one is at least five mm below that. At this point, I check for case damage, and don't find any. The action brackets fit onto adjustable (vertical) bolts screwed into wooden supports, and there's a horizontal steel U-channel beam supporting them underneath. Everything appears to be straight. I do wonder about the replaced music desk, though. The customer says it disappeared during a move (better to deliver without it, than to show up with a damaged one? The support brackets are fine.) So, for the first time ever, I adjust the action bracket height by raising that vertical support bolt. Wow, talk about a hot button! With the slightest turn, hammer-to-string alignment changes, dampers move around, and even the amount of damper pressure on the strings changes! Hoo-boy! So at this point, I need advice for finding the right position of the action relative to the strings. I know that the horizontal (upper) action support bolts are often bent down to resist the upward forces from playing, so I measured the distance from the top of each bracket to the edge of the plate (see pictures). It's 120 mm on the bass bracket, 115 mm on the middle one, and 112 mm at the top. Key dip: C1=8 mm, C2 = 9.5 mm, C4 = 11 mm, C5 = 10 mm, C6 = 11 mm, C7 = 10 mm. Keys are level. If the action is lower in the bass, wouldn't that raise the front of the keys, creating more dip? So this is a puzzler that I don't have the answer for. Once I get the action close, I can regulate to fit, but obviously getting it right to start with will greatly eliminate the amount of later work. The question, then, is: how is the height of the lower, vertical action support bolts set at the factory? --Cy-- Cy Shuster, RPT Albuquerque, NM www.shusterpiano.com www.facebook.com/shusterpiano -------------- next part -------------- An HTML attachment was scrubbed... URL: <https://www.moypiano.com/ptg/pianotech.php/attachments/20110905/4e39291e/attachment-0001.htm> -------------- next part -------------- A non-text attachment was scrubbed... Name: SNC00009.jpeg Type: image/jpg Size: 36104 bytes Desc: not available URL: <https://www.moypiano.com/ptg/pianotech.php/attachments/20110905/4e39291e/attachment-0003.jpg> -------------- next part -------------- A non-text attachment was scrubbed... Name: SNC00013.jpeg Type: image/jpg Size: 35447 bytes Desc: not available URL: <https://www.moypiano.com/ptg/pianotech.php/attachments/20110905/4e39291e/attachment-0004.jpg> -------------- next part -------------- A non-text attachment was scrubbed... Name: SNC00014.jpeg Type: image/jpg Size: 32642 bytes Desc: not available URL: <https://www.moypiano.com/ptg/pianotech.php/attachments/20110905/4e39291e/attachment-0005.jpg>
This PTG archive page provided courtesy of Moy Piano Service, LLC