Is the early wood the weak link to cause set?

[Selfbowman]

If early wood is not as dense and would crush first does it not domino the set thru out the limb.
I’ve heard that what is in the middle of the limb does no work it just holds the tension on the back and
Compression on the belly apart so to speak.
So What is the fix to compensate for the weaker link?
Possibly by trapping. I’m looking forward to hearing the take on this from everyone. Especially Marc, Mark , Bownara, DC, and Badger to mention a few.

[Dances with squirrels]

Before we make too many assumptions regarding the tendencies of clearly designated early and late wood in some species, let's be sure to keep diffuse porous woods and tropical woods in mind. They take set too.

[Selfbowman]

Thanks dances with squirrels good point. I can’t agree about crooked wood makes a better bowyer though. There is art in straightening the grain also. I’ve built a couple snake bows following the grain and built a bow that you can drop a half dollar thru mid limb . Bows full of shock and so on none of which made me a better bowyer.  Arvin

[HH~]

Yes, even non open grained wood takes set.

We talking Osage the is but little doubt that early chaulky growth is the weak part the wood. Specially if that early growth is a rather thick line. It really reduces the density of the stave as a whole.

If noticed when doing statics if you have really nice rings but the ratio of early to late leans toward large early chaulky and they are thick the wood will try to separate in that line. Yes , that is the weakest part of Osage.

HH~

[Selfbowman]

Shawn I think it applies to lots of woods . Oak, walnut, maple, pine, lots of them. Maybe not blood wood , Purple Heart etc.

[Dances with squirrels]

Send yer snakey staves to me then, Arvin. The snakier the better! 

[Selfbowman]

Don’t have any .I like better bows.😁😁😁😁just a dig in fun. Please don’t take that personal. Arvin

[HH~]

Yeah, I always see these snaky bows on the Podium. Aaaah, not really. Well, not ever.

But that early growth is however the weak part of the Hedge for sure.

Shawn~

[Selfbowman]

The bull crap is getting old fast enough. Can I hear from some smart guys that can put things in language that the country bow can understand?

[Dances with squirrels]

It's all good Arvin.

Podium. Lol. Took me a minute to figure out what the heck you were even talking about.

Sounds like a good name for the snakey osage bow I'm working on. "Nopodium".

[George Tsoukalas]

Adapt and overcome. If there is a lot of early wood, leave it a little wider. Jawge

[mmattockx]

I’ve heard that what is in the middle of the limb does no work it just holds the tension on the back and
Compression on the belly apart so to speak.

This is mostly correct, but the inner core of the limb isn't doing nothing at all, it is just contributing much less than the wood near the surfaces.

For a rectangular cross section limb the stresses (and strain) are zero at mid thickness and increase linearly to a maximum at the surface, both back and belly. This arrangement means that the majority of the work/energy storage is done in the wood near the back and belly surfaces. For the rectangular cross section it works out that half the work is done in the outer 15% of the limb.

Say you have a limb that is 0.5" thick, 50% of all the work is being done by a strip that is 0.075" thick on the belly and back. The other 50% is done by the 0.35" of wood in the core, which is why I said it doesn't do nothing, but it contributes at a much lower level per ounce of wood.

So What is the fix to compensate for the weaker link?
Possibly by trapping.

Your fix (if there is one) depends on if the early wood is weaker in tension, compression or both. If it is weaker in both then there won't be much you can do aside from lowering the stresses everywhere by making the bow longer and/or wider in the limbs. If it is only weaker in compression then trapping will help by reducing the stresses on the belly. It won't solve the problem but it will improve the situation for any tension strong wood.


Mark

[Pat B]

I think the weak link in the bow building process is the builder that doesn't understand the properties of the wood being used or practice appropriate tillering methods and/or the design considerations for the wood that is used. Wood bows will take set, it is inevitable because of the properties of wood and what it is being asked to do. Set is not necessarily a problem in a wood bow. Some of our wood bow icons from history indeed liked some set in their bows. We are not dealing with modern materials and we should not expect a wood bow to act the same as a FG bow; oranges to apples.
 Of course early wood is weaker than latewood and especially in ring porous wood like osage, mulberry the oaks and others. But I haven't noticed that the early wood adversely affects the strength or performance of a bow. Some of my best, hardest hitting bows have been osage with paper thin rings. With a good solid, clean back ring, proper tillering and design methods and patience anyone can make a well performing wood bow.

[Selfbowman]

Thanks Pat I appreciate what you said . I am not trying to build a hard hitting shooter . I’m going for the hardest hitting bow for flight. Arvin

[PatM]

I think you're sort of wondering if the crunchy layers are sort of like a bad glueline in a laminated bow and if they actually allow some creep in addition to the more common types of set caused by compression.