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Old 03-11-2009, 10:30 AM
Howard Klepper Howard Klepper is offline
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Quote:
Originally Posted by SteveS View Post
I have built both, but prefer parabolic bracing, make that parabolic lattice bracing. The term parabolic is applied in a general sense to indicate that the transition in height is very gradual, but there is no way any one's braces are actually parabolic.
As Steve says, no one actually shapes braces to a parabolic curve. When I first heard the term, I asked the person using it (who I believe originated the usage) if he knew the quadratic equations for the parabolas he used. He ignored the question. I have never seen or heard of anyone who plotted a parabola and used it as a model for a brace. Conclusion: "parabolic" is just puffery; a misleading term that is being used to imply a scientific knowledge and geometric precision that does not exist. All it means in connection with bracing is 'convex.'

Scalloping is not intended to be a way of maximizing structural strength or rigidity with a minimum of mass, which is probably what the OP's engineer friend was assuming. It is a way of shaping tone by introducing a tendency toward certain nodes and antinodes in the modes of top vibration. How it does this is a matter on which there is disagreement, and which could be the subject of a lengthy treatise.
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