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Pretty interesting. I have no idea how much work it is to do this analysis, but could you also model reverse kerfed linings without the top and back plates and with the top and back plates for completeness since the original post was about reverse kerfed linings? Would you also be able to model deflection without linings at all, but with the top and back plates?

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

Excellent work, Jim Finally we can lay this old argument to rest. The results are pretty much what I expected. The difference you feel on the free rim is still there, but dwarfed by the effect of the geometry when the box is closed.

As for impedance difference due to mass, maybe we should be using denser woods for linings? Or just make larger triangular type. I make supersize dentellones for armrest bevels, so I could try doing that the whole way around and see what happens.

Thanks Jim! I should have been more patient.

This is great stuff. It confirms my suspicion that any difference in stiffness is negligible after the plates are on. Still, the added mass probably has some degree of effect on how the body performs but that’s far out of my element. I’ll keep using solid linings because they benefit my building style it maybe I should use denser material.

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Bryan Bear PMoMC

Take care of your feet, and your feet will take care of you.

I suspected this result from a more scientific review, as I stated earlier. So, I will keep using the linings I prefer: homemade, regular kerf, but rectangular (not triangular), with the one unglued edge rounded over with a 1/4” roundover bit, and overall larger than store-bought lining. It is easy for me to make it myself, and it is super easy to install. It provides more mass than store-bought, without being as fussy to install as reverse kerf or laminated lining. And I like how it looks.

Thanks so much for the work that went into the mock-ups!

Wow! I stepped away for a couple of days, you guys went to town! Thank you for the thorough answer to my questions, Jim and everyone.
I glued on regular linings today, for the 2nd body I'm building, so glad to have confidence in the results.
The truth is I should probably focus on more fundamental concerns like making sure I avoid gaps as I'm putting on the clothespin clamps.
The sapele and khaya neck blanks showed up in the mail yesterday as well, so I suppose soon I'll know more about that too.
Thanks! Bill

The reverse kerfed linings scenario will be less stiff than the solid linings, which is why I ran the solid linings in the model. They represent the most extreme common building practice that I'm aware of. The reverse kerfed linings should be close to the solid lining in stiffness as it creates a cored structure with the side, but once the plates are it doesn't matter anyway.

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Jim Watts
http://jameswattsguitars.com

I use reverse kerf linings because they look cool and seem to contain the glue squeeze out better.

Amazing analysis Jim

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It's not what you don't know that hurts you, it's what you do know that's wrong.

I associate the type of linings with certain buyer groups...likely because we see these groups for repair and setup work, as well as bringing the finish and setup work up to standard on new instruments.

The traditional Gibson/Martin buyers seem to ask for standard triangular kerfed linings, and for really old repro work on old Gibsons, solid linings.

For the customers that thrive on what Acoustic Guitar Forum offers (i.e., a cutaway SJ with highly figured woods, sound port, arm bevel, asymmetric snakeheaded headstock, Gotoh 510 Delta tuners in gold and custom wood tulip buttons, a five piece neck, segmented or geometric design wood rosette, and one of those chunky 'smile' volutes), the reverse kerf linings look like they belong on the instrument, unless Ryan '3D' linings are available.

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A constellation only takes shape when one maps the whole.
- Beth Brower