May I add some suggestions after reading about this problem last week whilst on a family holiday at Broadbeach.. I decided that the beach was more important. There have been some suggestions that the jack is not clearing the hammer butt and now causing the hammers to bobble. Matthew has adjusted the let off and lost motion. 1/16 let off is ok in the bass, but may I suggest looking up Kawai specs. 2.5, 2 and 1.5 mm for let off. Someone has suggested to increase the aftertouch by removing front touch paper punchings. After observing the hammer line to be all over the place, the first place I would look would be measure the hammer striking distance.. or your hammer blow. 46 mm from string to tip of hammer. Checking this and then adjusting the position of the hammer rest rail would be the first place which I would look. My preference in doing this all would be removing the action and keys. Looking at condition of keyframe felts..and condition of keybed. some came loose. Fit action and measure hammer strike. It may help to change to 45mm. Adjust by moving hammer rail and gluing felt to the felt blocks. I forgot. inspect condition of hammer rest cloth. Adjust let off and then damper spoon lift.. This is how it is done in the factory. Then remove action and then re fit keys. How is the balance rail and keyhole.. Tight? Cleaning the key pins is a great idea. Adjust capstans. yes, Kawai uprights require a little lost motion. The method mentioned of hammers moving backwards a little when the hammer rail is pulled backwards is correct. Another way is to trip the jack slowly and make sure the jack slides under the hammer butt. What about the jack stop rail ? Is there clearance? That's a trick that was played on all apprentices. We never forgot after that. Hammer catching (checking) 15mm or 5/8 inch.. You could go a little smaller, but Kawai's 15 mm is a slightly large 15 mm. The damper spoon lift in the factory is quite early, so I would not be too concerned about making the damper lift later. After all these adjustments, you can then tell if this problem is keyboard related i.e. the level of the keys and then I would look at key dip. Seems strange to me that a tech would have previously made the key dip shallow.. Older Kawai's were 10.5mm . I do not know if there is a geometry problem with this action, but there is not much you can do about it, since the price to change would be more than the present market value. The actions worked when new and the piano was at the lower price end of Kawai's models. Shouldn't have too many problems now however check the cushion (red) felt under the hammer butt leather. Some later models the felt expanded and the leather has a bump, and also check the end of the butt leather (further up the leather). My 1994 125cm upright has that and I do have problems with bobbling hammers..I decreased the strike distance. I am replacing the hammer assembly soon. As with tonality, it is hard to judge tone on an action that is not working correctly, and maybe that this piano hasn't been voiced in about 20 years. Are the original hammers no underfelt on white wood or underfelt on mahogany? Hopefully they aren't the underfelted white wood with green impregnation.. they were hard as goats knees then!! I think I have left something else out but still in holiday mode.. Brian Wilson _____ From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf Of Ed Sutton Sent: Monday, 11 May 2009 7:15 PM To: pianotech at ptg.org Subject: Re: [pianotech] Hammer Line Issue Here's Matthew's first post: >I went to tune a clients piano today. It is a Kawai Console, year 1986. >The very first thing I noticed was the hammer line was totally screwed up. Some of the hammers were resting on the rail, and others were off the >rail. I unscrewed the action bracket nuts and pulled the action back a little until all the hammers were resting on the rail. " What is the likelihood that the piano had overly strong damper flanges, un-noticed for 22 years ? The customer didn't complain of bobbling hammers. That problem occurred after Matthew adjusted the capstans and let-off. We are into the second or third stage of treatment without diagnosis. ES No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.5.325 / Virus Database: 270.12.13/2091 - Release Date: 05/10/09 07:02:00 -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech.php/attachments/20090511/01a23ce1/attachment.htm>
This PTG archive page provided courtesy of Moy Piano Service, LLC