Thanks David A for the update I am interested in this as well. Dale -Hi Bob & Frank/All I appreciate your words of support Frank and the confirmation of your research & may I just say that Bob & I did have this discussion & the merit of his suggested method uses more of the complete motion to assess overall action ratio. Dave Stanwoods comments about the action ratio gauge being a tool to get you close but should not consider it a scientific tool is also notworthy & for microspoic analysis I suggest more complete study before pinning down a final conclusion However for quick work in the field or on the bench the action ratio gauge set up with the 6 mm foot will give a close infield ballpark reading. For example if the gauge reads a hammer rise of 36 mm, this is a 6 to 1 ratio. Note thought It is 9 or 10 mm short of using a complete hammer blow distance of 45 mm which I see in many Stwy pianos & others I thought about doing some experiments by modifying the foot on my gauge to 8 mm. A 6 to 1 ratio with An 8 mm foot will cause 48 mm of hammer rise. In which case the let-off button would need to be screwed up on many actions which is only slightly inconvenient but This modification would take into account more of the hammer travel as Bob suggested. Of course a lower ratio say 5.5 to 1 creates only 44 mm of hammer rise so in most c ases would be very workable. Routinely though action ratios seem to average something like 5.3 to 6.3.Yes, there are anomaly on either side of this.. I think I'll do some comparison testing of a 6 mm & 8 mm foot on the action ratio block & see how much of a difference is had by allowing more of the entire key stroke come into the equation. This may be especially important when diagnosing the angled capstan systems we've been discussing. I will say even using it with the 6 mm foot has given me a Polaroid snapshot & better quick idea to begin assessing the direction of the entire job than using nothing at all, which is what I do when I have no tools handy. How bout you'all? Dale In a message dated 3/15/2009 3:09:38 P.M. Pacific Daylight Time, pianoguru at cox.net writes: Dale Erwin’null practice of measuring hammer movement for a predetermined key movement is much superior for determining the ratios. When this came up a couple of months ago,20I pointed out that the weakness in this (which in Dale'null method used only a fixed, limited portion of keystroke) lies in the (unpredictably) changing ratios as the action goes through its motions. I prefer to use the whole keystroke, using a fixed setup of 1.75 inches blow (only for measurement - I might change it later); .040 null (ditto), and an otherwise regulated note, to see what kind of dip it produces. I think this gives me a more accurate feel for the whole distance ratio, and has the advantage of using larger movements which I think increase the accuracy. Bob Davis Need a job? Find employment help in your area. Live traffic, local info, maps, directions and more with the NEW MapQuest Toolbar. Get it now! -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech_ptg.org/attachments/20090318/8910b14a/attachment-0001.html>
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