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Robbie's latest video has prompted me to raise a question that I've had for some time. While I can understand that using reversed kerfed linings can make sides "stiffer" when the rim set is sitting on its own, I don't buy that they are any stiffer once the top and bottom are in place. After that, the edges don't move i.e. they are as stiff as they can be. So where's the advantage in that respect?

Fully laminated sides I think are a different story. They are much more robust and I can see they could potentially absorb less energy than non-laminated sides. Whethor or not the difference would be audible, I'm not sure.

Pat

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There are three kinds of people:

Those that make things happen,
those that watch things happen,
and those that wondered what happened.

The sides do flex a little under the rotational energy of the strings. Stiffening up the rims helps with this. The other thing about stiffer rims (if you buy the theory) is that they help to not absorb as much of the vibrational energy of the top and back plate.

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Brock Poling
Columbus, Ohio
http://www.polingguitars.com

Pat: The reverse linings do stiffen the sides quite a bit without top or back. You raise a very good question as to if they are any stiffer after gluing on the top and back. My gut feeling is that they are if only marginally. That aside I think the big advantage of reverse kerfing is how much neater I can do brace in letting. I also find the reverse easier to glue in due to parallel faces. For me the reverse is also easier to manufacture. These factors are enough of a benefit to be converted to dedicated use of reverse kerfing.
Tom

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A person who has never made a mistake has never made anything!!!

the reverse kerfing does little to stiffen the sides , they do however act as a truss to make the bend more rigid. This does little in changing the physical properties of the side wood. The uncut wood of the reverse kerfing will help to make the side rigid only due to the 2 parallel plates of wood. There is no physical change to the sides woods shear or yield strength.

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

I use reverse for the back, looks better when looking in the finished guitar. I really doubt it helps the general box stiffness in any significant way. If you want truly more stiffness, try solid bent linings.

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Build log

It will be functionally more similar to a solid lining as opposed to discreet members. I suppose it depends on your definition of stiffness, though. The only real purpose it serves is to increase bonding surface area for the top and back, after which assembly they are likely very close to being out of the equation.

That is my point Todd , I agree . I think kerfing is just that a piece to allow surface area for glue. That is all it is after that it is just personal taste .

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it