Hi Paul, I have to side with Ron N. Measuring the length of A4 makes more sense. On quick review of scales I have studied, the length of A4 ranges from 400 to 429mm. 415 is a good median, but obviously the shorter length (400) is in a spinet, and the longer length (429) is in a concert grand. Judging where your piano falls in the range from spinet to concert grand can give you a better length to target. Also consider that the difference in length from note to note, at A4, would be about 20-22 mm. Regarding C8, there is nothing sacred about a 60% break point. Depending on the v-bar termination material, radius, and deflection angle, a higher break percent can be tolerated in the highest notes. To expect that the maximum length for C8 would be 52, just because it exceeds 60% break point, ignores the reality that many scales historically go well beyond this length. 54mm is not unusual, without presenting any problems with string breakage, when mitigated by other factors (mentioned above). This is a difference of only 2mm, but the difference from note to note in this part of the scale is only 2 or 3mm. Also, it is difficult to accurately measure shorter lengths at C8, than at A4. Frank Emerson
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