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Greg E wrote:
"Alan you make some good points about us all needing to use the same apparatus and method to have the data be really useful. I don't have a deflection testing setup yet, so I'm game to build whatever is a reasonable for all of us."

Actually, I see no ned for us all to do the tests in the same way, just so we get comperable results from our different setups and, more importantly, express them in ways everybody can use. There are several methods for finding the Young's modulus along and across the grain. Each of them has it's own drawbacks in terms of accuracy, cost and time. It would be nice if we could get everybody to 'calibrate' their own setup, using some 'standard' pieces of wood or something, but realistically that's not likely to happen. This will necessarily limit the usefulness of the comparative data. However, I don't see this as being a big problem for us. None of us is working so close to the line, as it were, that a small error will make a large difference. It would be one thing is we were building these things to go into orbit, say, where a few grams one way or the other would make the difference between success and failure. With a bunch of builders making non-standardised items, and judging them subjectively for tone for the most part, we're going to get more from watching trends than exact numbers. Knowing that, say. less dense tops work 'better' for classicals, and more dense ones for Bluegrass Dreads, will help us all to sort our tops for best utility. Some comparitive data on stiffness ratios will help us to figure out just how floppy a top you can get away with and still make a good Jumbo.

Just wanted to know if anyone has gotten any further on this matter ?

Lars.

Lars:

I'm still interested in pursuing this topic, but [as most small time builders] lately my personal life has taken priority over my building projects.

Perhaps this thread can be revisited by others with more time and resources, so an actual sharing of data can occur.

Thanks... Greg

As soundboard shape affects the results is there a standard size they should be trimmed to, to achieve consistent results?

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Formerly JJH

I learn more from my mistakes than my successes