Hi JD Hey. I've been gone but Thanks for chiming in on this & verifying what I've ben saying. I wasn't sure there was any interest or perhaps It's use just wasn't clear. HOWEVER this gauge suffers from one obvious shortcoming and that is its resolution to only 0.1 degrees, which might not sound much when you say it quickly, but in practice is equivalent to a card's thickness (roughly 9 thou or 0.22mm) at the string rest given a back-length of 5 inches (127 mm.), and a very significant percentage of the actual range of angular deflection applied in practice. As regards downbearing, an angular deflection of 0.1 degree represents about 70 pounds-force at the bridges when applied throughout the typical grand piano. >From what I can see of Dale's device and gauge, even if his gauge stepped (go no-go), as it seems to be, in steps of 5 thou, he is still able to measure the angle with half the tolerance of the Wixey gauge, ie. to within 3' or 0.05 degrees. With a continuous wedge gauge it is possible to achieve even better accuracy. This is correct. The thin brass wedge p[pictured is in .05 increments & Is a handy tool from Dana Masaglia. Since I'm usually only interested in net bearing figure , this 25 cent jig does see it quickly & nicely. It can also be used for a quick reference as the go no go tool as you say. SO often I follow up on Estimates where another Technician has stated that the piano in question had bearing as checked with the Lowell gauge only to find after it's unstrung that it had none at all. My caution to folks is beware giving these findings as absolute when bubbling around. Unless you can see an overall net bearing with a simple gauge such as this there likey is precious little bearing or crown in the system being anaylized. Know what I mean? At 9:05 am -0400 4/5/07, Dale Erwin wrote: On a 5 inch string segment yielding a gap of .065 thous (as measured with the gauge in the picture) reveals that there is about 3/4 of a degree of residual net bearing. Now this is a new board set up at 1 1/2 degrees. So I've squashed the board 3/4 of a degree. In fact in this instance Dale's measurement could hardly be more accurate since sine(3/4) x 5" = 0.0654" but even supposing Dale is using a go-no-go gauge with 5 thou steps and went to the 70 thou step rather than the 65 thou, the calculated angle would be only about 0.05 degrees different. I've photoshopped Dales picture to make it quite clear where the gauge rests, on the speaking length in front of the pins. That said, I'm sure Dale will agree that although this method is quite accurate for measuring and demonstrating the angle after the event, it is not the perfect method for setting up the angles before the piano is strung. Indeed. Spot on. Dale JD ************************************** See what's free at http://www.aol.com. -------------- next part -------------- An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/20070508/cf4e762c/attachment-0001.html -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: image/unknown Size: 21842 bytes Desc: not available Url : https://www.moypiano.com/ptg/pianotech.php/attachments/20070508/cf4e762c/attachment-0001.bin
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