Is the early wood the weak link to cause set?

[Badger]

  I always feel more comfortable with the belly ring at least 1/8" thick. I don't think I have ever finished a bow that had an early wood belly. I have had plenty of osage staves with paper thin rings that worked out great. I have actually gotten to where I like the thin ringed osage. It doesn't seem to make much difference as long as the belly ring is late wood. Just an observation on my part I don't claim any factual expertise on.

[mmattockx]

it could be built, but I do not believe you will get the energy storage. for example
a hickory bow vs. an otherwise similar dimensioned bow constructed with a front and back hickory lam on a balsa core

Ah, I understand. If you keep the external dimensions the same then you wouldn't get the same energy storage, because the core is normally doing some work in storing energy. But building a bow as you describe with the dimensions adjusted to suit the construction method should be the same or better (due to higher efficiency in how it uses the wood) than a one piece bow. It would essentially be a wood version of a foam core fibreglass lam bow and those work just fine.


Mark

[Selfbowman]

  I always feel more comfortable with the belly ring at least 1/8" thick. I don't think I have ever finished a bow that had an early wood belly. I have had plenty of osage staves with paper thin rings that worked out great. I have actually gotten to where I like the thin ringed osage. It doesn't seem to make much difference as long as the belly ring is late wood. Just an observation on my part I don't claim any factual expertise on.
[/quot

I’ve  been attempting this Steve but to hit our weight classes makes this a bit difficult. For me at least. Arvin

[scp]

Stiffness is just resistance to bending. We don't want a bow that bends, we want a bow that resists  bending. Like in a hydraulic system, pressure is a measure of resistance to flow, not a flow rate. So, when I look at it from that angle, I want a bow that has the most resistance to bending as it can without failure.

    Still needs to bend though.    Bow woods come in very low resistance to bending and very high.  Both are highly regarded as long as they bounce back.

"In terms of looking at the raw mechanical data of woods, the best bow woods tend to be those that have a low MOE and a high MOR. (Stated another way, the best bow woods tend to be those that will bend easily, and not break.)"
From https://www.wood-database.com/wood-articles/bow-woods/

[scp]

One thing I will say is remeber the balanced seesaw (teeter-totter?)....IF we manage to balance the force back and belly we get significantly less set. .... Trapping may well be the way to better distances for you.

Yes, IMHO what matters most is the well balanced relative ratio of the tensile strength of the back half and the compressive strength of the belly half; as well as the relative ratio of MOR to MOE of the whole stave.

Cf. https://www.wood-database.com/wood-articles/bow-woods/

[ssrhythm]

Early wood on the belly surely just sits there passively.   About like roughing up a belly surface with a rasp.   It can't have any functional integrity.

It doesn't,  and that's why I think ( key word ) it going into the belly is detrimental to a bow.

Detrimental how?  Unless its a pyramid bow or a bow with extremely thick late wood growth rings, there has to be some early wood coming into the belly surface.  I'm just thinking about the osage bows I've built...how could you not have early wood coming into the belly of the working portions of the limbs without it being a pyramid design?  I agree...its not just sitting there passively.  It is getting compressed and sheared and doing whatever weak, pithy wood does when it gets compressed and released, but for it to contribute any way to set, it's physical properties would have to overwhelm and overcome the physical resistance-to-compression properties of the latewood layers it's sandwhiched between.  If the latewood in the compression plane is able to withstand full draw without it's cells crushing an colapsing, it will bounce back, and I can't see how any amount of that pithy early wood could stop it. 

[PatM]

Early wood is barely even continuous in structure.  I think we're thinking that layer of early wood exposed on a belly has about the  structural strength of a coat of glue with some sand strewn on it.  It would be like dead weight.  Might as well just sand it off .although the weight has to minimal.

 I think people wondering if it contributes to set are thinking it might creep or break down and allow some shifting of the growth rings perhaps. 

[Selfbowman]

Yes Pat I’m in that group. Making it the weak link.

[HH~]

Think of an Oreo cookie . . . . .?

Snap one


Then scrap the whyte guts out put the black outer shells together now snap one.


Physics by Hostess and Keebler

Not hard for a Nug to figger.

Shawn~

[sleek]

Think of an Oreo cookie . . . . .?

Snap one


Then scrap the whyte guts out put the black outer shells together now snap one.


Physics by Hostess and Keebler

Not hard for a Nug to figger.

Shawn~

I like that. And I just gained two pounds experimenting.

[RyanY]

Early wood is barely even continuous in structure.  I think we're thinking that layer of early wood exposed on a belly has about the  structural strength of a coat of glue with some sand strewn on it.  It would be like dead weight.  Might as well just sand it off .although the weight has to minimal.

 I think people wondering if it contributes to set are thinking it might creep or break down and allow some shifting of the growth rings perhaps.

If this is the case, how would board bows or bows where the early wood is not exposed on the belly be effected?

[PatM]

Board bows of typical orientation would actually have more early wood exposed as linear lines but they wouldn't have that  "between lam"  shear potential.

[RyanY]

Board bows of typical orientation would actually have more early wood exposed as linear lines but they wouldn't have that  "between lam"  shear potential.

That’s my thought. If the shear potential is why early wood is a weak link, then it seems that board bows would take less set on average than stave bows.

[sleek]

Board bows of typical orientation would actually have more early wood exposed as linear lines but they wouldn't have that  "between lam"  shear potential.

That would theoretically make a big difference, and its my understanding that this may be the best orientation for a bows rings if you can get good clean wood.

[RyanY]

Board bows of typical orientation would actually have more early wood exposed as linear lines but they wouldn't have that  "between lam"  shear potential.

That would theoretically make a big difference, and its my understanding that this may be the best orientation for a bows rings if you can get good clean wood.

Would be a good experiment to find a wide flatsawn board with enough width for a quarter sawn/rift cut piece and a flat sawn piece to build a couple identical bows from to test. Still not totally homogenous but as close as it one could probably get.