This is an intriguing problem, David. Can you offer any more data? For example, how high are the strike weights? The hammer weights (more or less)? How low is the DW and how high is UW (more or less). You say friction is not a problem, any data? Why do you deduce from the pianist that inertia may be the problem? You say, "The only area that can be responsible for the added inertia are the higher strike weights." Most likely true, but the whole package needs to be considered as (judging from your history on this list) you already know. How low is the action ratio now? Are you able to supply measurements along with method of measuring? Should the overall AR be low for this action, relatively heavy hammers and (possibly) hammer friction centers just on the verge of being too loose will cause the action to feel uncontrollable, and repetition might suffer. The sense being, that once the key is struck, control of the hammer becomes a guessing game, especially for rapid playing. Can we assume that the action spread, elevations and hammer bore are not in question, or at least not likely seriously so? May we have more? Nick Gravagne, RPT Piano Technicians Guild Member Society Manufacturing Engineers Voice Mail 928-476-4143 -----Original Message----- From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf Of David Love Sent: Tuesday, March 16, 2010 8:55 AM To: pianotech at ptg.org Subject: [pianotech] Action inertia FW versus SW We often discuss the issue of excess inertia in an action due to too much lead in the keys. But how does the inertia compare if you change the leverage and substitute high SWs and low FWs? I have recent customer who has asked me to assist him with an action that he is complaining about. The FWs are pretty low and uniformly located nearer the balance rail. The strike weights are fairly high, the balance weight is low (34 grams), friction is not a problem. From our discussions about what he doesn't seem to like I deduce that it's an inertia problem. The only area that can be responsible for the added inertia are the higher strike weights. Interestingly, this piano is a Steinway that had lots of lead and very high action ratio and relatively light hammers before work was done to it. The change was to a low action ratio, low FW but high SW action and he doesn't like it any better. Comments? David Love www.davidlovepianos.com -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech.php/attachments/20100316/e93b5cda/attachment.htm>
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