>> ..."But the shape of the curve wont' be an arc" > I've heard that argument before. I'm not so sure that is > the case, and even less sure that it is of any consequence. > > > Another method for scribing a large diameter arc is to > convert the radius data to "rise" over a given distance, > say 6'. Construct a bow, as in an archery type bow, where > the string is music wire secured by tuning pins at each > end. The frame is an otherwise straight wooden beam, bent > by the tension of the string. Adjust the tension until you > measure the correct "rise" for the desired radius. Trace > along the edge to transfer the "arc" to the work piece. Of > course, bending the work piece itself has essentially the > same result. I am quite thoroughly sure this does not produce an arc segment, but haven't yet seen anything to indicate that any one crown contour is inherently superior to any other. Ron N
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