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So... solve my riddle...


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I've always heard that a good glue bond will actually make the joint stronger than the wood - do you agree?

So afa a les paul neck pocket: why would a longer tenon make any difference at all?  at a short tenon joint theorhetorically the two pieces become as strong as one piece of wood.  perhaps stronger.  It would seem that extending the neck piece would have no benefit whatsoever given that you agree with sentence one.  I suppose by extending the glued area the strength you get from the glue joint is more because there is more glue joint... but it should already be as strong as the wood itself.  thoughts?

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Principals of physics still apply. Just because it won't break at the glue joint doesn't mean it won't break at all. With the neck being a lever and the joint being a fulcrum, the pocket and gluing surfaces have to at least be enough to withstand the amount of force that can be applied by that lever and fulcrum assembly. There can be such a thing as overkill though. I make huge long tenon joints purely because it makes me feel better about the whole thing.:)

SR

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scottr - you cracked me up with that last line!  "they're my believies - they make me feel better"

I hear ya on the physics, and always good info - thanks for that.  I've seen your long joints and I have to admit I was thinking "why aren't they all like that, or none like that?"  Long story short - i believe you but I don't know why.

I suppose the continuity of the fiber is the factor.  Then again would it be a stronger joint if the tenon was multilam?  that's probably rhetorical.

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If you have a tenon that goes under the pickup, the weak point is the 90 degree angle below the end of the fretboard and the actual tenon under the pickup cavity. Apply force to the lever of the neck and it will typically break at that point quartersawn timber at that point will be stronger and laminates stronger still.. The point of having a deeper or longer pocket or even a longer tenon is to provide enough gluing surface to protect that weak point and keep it from acting as the point of the fulcrum.

I hope I am making sense.

Back to your original statement of glue bonds being stronger than the wood itself, how that is generally illustrated is like this: two boards are prepped and glued together. Once properly set and dry, force is applied in a manner intended to break them apart at that joint. What happens (if the glue joint is done correctly) is that the boards do break apart - to one side or the other of the glue line, with a little bit of wood from the board that broke still covering the glue joint. The bonded wood was stronger than the non bonded wood adjacent to it.

SR

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your explanation on the tenon is crystal clear.  makes sense.  Hadn't considered the deeper neck tenon and now that makes even more sense.

afa glue joint... I have seen the proof of that.  I'm a believer, nice illustration tho.

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