Author Topic: vertical grain is stronger than horizontal grain  (Read 33712 times)

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Offline Scyth

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Re: vertical grain is stronger than horizontal grain
« Reply #45 on: January 22, 2019, 12:13:55 pm »
Again I repeat . . .

“The identical piece of wood -

Vertical Grain favors compression tension
 
Horizontal Grain favors elastic tension

(. . . pick your poison . . . )”


regards,

John
"Retirement is not a word in the dictionary of craftsmen
and I will carry on my work a long as I can . . . "

- Yang Fuxi

Offline Selfbowman

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Re: vertical grain is stronger than horizontal grain
« Reply #46 on: January 22, 2019, 12:56:12 pm »
In one of my early bows I built a Osage bow I think 68" or so. The stave was not very wide. I managed to get 7/8 inch limbs to mid limb. The bow limbs almost sq.  Surprisingly the bow took very little set. The bow had excellent cast. My mistake was not following the grain and the bow kept splintering. I liked the cast and put two or three patches on. One of those you just don't want to give up on. Happens a lot in early builds for some of us! Any others out their have the same results. Most 1-1/4 bows I build today take more set. Maybe I need to try another one 7/8 wide. Arvin
Well I'll say!!  Osage is king!!

Offline bradsmith2010

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Re: vertical grain is stronger than horizontal grain
« Reply #47 on: January 22, 2019, 01:19:17 pm »
what was the draw weight of the narrow bow,,

Offline Artus

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Re: vertical grain is stronger than horizontal grain
« Reply #48 on: January 22, 2019, 01:54:46 pm »
I think I can summarize, that nobody said my plan wouldn't work.
So I just give it a shot. Me feeling tells me, that ash is a perfect candidate for this. My opinion is that ash is good in tension and bad in compression, so the wood can benefit from the vertical orientation. In addition ash splits nicely, even the logs small in diameter.

I hope I get around tuit this week. Otherwise I'll try it next week.

Offline PatM

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Re: vertical grain is stronger than horizontal grain
« Reply #49 on: January 22, 2019, 02:36:40 pm »
As noted there is nothing new or revolutionary about this idea.  It has been done thousands of years ago and is still done today.   As to why it's not done as a simple solution it's likely because wood tends to have grown over defects closer to the core.   A perfect exterior stave can be a mess near the center but had plenty of time to grow over.

Offline gfugal

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Re: vertical grain is stronger than horizontal grain
« Reply #50 on: January 22, 2019, 03:19:58 pm »
I think the edge grain bows prove,,,there is no performance advantage,..I'm pretty sure the world record setting bows Badger makes are not edge grain orientation

Just because the world record bow isn't edged grain is no proof that edge grain bows couldn't be made to be world record setters some day. I'm not trying to argue that edged grain is superior to parallel grain, just that it shouldn't be dismissed. I don't know how badger feels about edge grain, I'm sure he has done it before. I would venture to guess that the majority of his bows aren't edged grain for whatever reason. In fact, the majority of all bows aren't edged grain (I've seen maybe two or three posted on here, and I haven't seen a non-board-bow self-bow yet). Therefore the ratio of them to parallel grain bows is pretty low. It's hard to make world record setters when they just simply aren't being made in general. Even the best bowyers can't perfectly reproduce those highest quality bows, even if they use the same wood, design, and skill while making them. You have to make enough to "stumble" upon that really fast shooter. I would argue that edge grained bows just aren't made enough to 1) discover/"stumble across" those real shooters, and 2) have the repetition to perfect the process of making them (as I'm sure they preferred to be worked differently in some ways than parallel grained bows). Although it's not a self-bow, or a world record setter, DC made a very good edge grain bow not to long ago shooting in the 190 fps at 10 gpp http://www.primitivearcher.com/smf/index.php/topic,63436.0.html. If anything that should prove they can be as effective as some of the best parallel grained bows.
« Last Edit: January 22, 2019, 03:35:50 pm by gfugal »
Greg,
No risk, no gain. Expand the mold and try new things.

Offline gfugal

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Re: vertical grain is stronger than horizontal grain
« Reply #51 on: January 22, 2019, 03:29:45 pm »
You really think the guys building 100's of bows aren't trying new things? ....and vertical grain vs horizontal grain isn't thinking outside the box.  It's done all the time!
I never said they haven't been made by the experienced members. I actually wasn't thinking specifically of edge grain when I wrote that, more of a flipped grain bows, or other radical designs and materials. However, I would say that edged grain bows aren't made that often, especially self-harvested/dimensioned self-bows. Of the hundred of bows experienced bowyers have made, how many are edge grain? Of all the bows that are made by everyone, how many are edge grain? I was trying to address the issue of why many aren't made, not that they never have been made. PatM suggests that it is probably due to practical reasons, with imperfections requiring larger diameter trees. And maybe that's the reason why. Having never made one myself I can't really say one way or another based on experience, it just seemed to me that it also has a lot to do with tradition. That was my point.
« Last Edit: January 22, 2019, 03:42:45 pm by gfugal »
Greg,
No risk, no gain. Expand the mold and try new things.

Offline DC

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Re: vertical grain is stronger than horizontal grain
« Reply #52 on: January 22, 2019, 03:36:10 pm »
I made one edge grain yew backed with edge grain maple. It worked well, actually it was my best bow up til then. The reason I did it was that the billet, if used conventionally, would have had a big sideways bend. I decided to turn it sideways and split it. I got a pair of sister billets that used edge grain was already nicely reflexed. I've since built very similar bows from plain sawn yew with edge grain maple backing that were a few fps faster. If I found another piece of wood with a sideways bend like that I would do the same thing again but I don't think there is much in it for speed. Maybe the fact that it was backed negated any edge grain advantage.
I think using your stave inside out will work, no doubt about that, but you will have a concave back unless it was a big tree.

Offline Jim Davis

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Re: vertical grain is stronger than horizontal grain
« Reply #53 on: January 22, 2019, 04:13:07 pm »
Again I repeat . . .

“The identical piece of wood -

Vertical Grain favors compression tension
 
Horizontal Grain favors elastic tension

(. . . pick your poison . . . )”

Just for the preservation of the language, I think you are confusing the word "tension" with stress.

"compression tension" is an oxymoron.


regards,

John
Jim Davis

Kentucky--formerly Maine

Offline bradsmith2010

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Re: vertical grain is stronger than horizontal grain
« Reply #54 on: January 22, 2019, 04:26:55 pm »
it mostly has a lot to do with experience,, (--) most of my bows are self bows or rawhide backed,, guys using other backings may have different thoughts about it,,for sure,, (-_)
« Last Edit: January 22, 2019, 04:36:01 pm by bradsmith2010 »

Offline Scyth

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Re: vertical grain is stronger than horizontal grain
« Reply #55 on: January 22, 2019, 05:05:29 pm »
Jim D. -

Nota bene :

On May 21, 2014 at 3:00 a.m.  I had an unexpected stroke : my left carotid artery was completely blocked and no surgically (or otherwise) intervention was possible.  I was 64 years of age.

I had to learn how to feed myself & to walk & to talk & to write, etc..

The struggle continues to reprogram my neural context . . .

& reading and writing  to this day.

regards,

Scyth

"Retirement is not a word in the dictionary of craftsmen
and I will carry on my work a long as I can . . . "

- Yang Fuxi

Offline willie

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Re: vertical grain is stronger than horizontal grain
« Reply #56 on: January 22, 2019, 05:38:32 pm »
there are some apple vs orange type comparisions being made that might be confusing this discussion.

a stave with a latewood natural back or a properly chased ring puts the most dense and strongest wood where the strain is the highest, and most will agree this is the best way to make a bow. But lets compare boards sawn the two different ways.

With a board, a flat grain surface of latewood may in fact not be as thick in some places as others, and the closely underlying early wood may be asked to handle more strain than it is capable of. An underlying imperfection in the earlywood may also be a hidden  point of stress concentration.

With a board of vertical grain, the most highly strained surface consists of latewood from each ring. Even thought the earlywood is also present in alternating bands across the most highly strained surfaces, The integretiy of the wood is being averaged between the dense and less dense, and a flaw in the weaker early wood is less likely to cause a splinter lifting on the back

In effect, (if there is no runout of the vertical grain), it offers a more consistent materiel to work with, and may appear to be stronger than the same piece of wood in a flat grain orientation, unless adequate dense  latewood thickness can be maintained on the both the back and the belly. Of course if your limb tapers in thickness, earlywood is exposed in varying degrees.

Offline PatM

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Re: vertical grain is stronger than horizontal grain
« Reply #57 on: January 22, 2019, 05:52:50 pm »
 Early wood also varies from species to species.  Compare Osage to say Maple.

 Though  many  would prefer an intact single growth ring for a back, it's pretty clear that some are hoping for board type orientation to be better in every way.

Offline willie

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Re: vertical grain is stronger than horizontal grain
« Reply #58 on: January 22, 2019, 05:58:22 pm »
Pat, nice of you to mention those differences. I have had good luck with edge grain maple for backing

Offline PatM

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Re: vertical grain is stronger than horizontal grain
« Reply #59 on: January 22, 2019, 06:02:02 pm »
 Yes, it's very homogenous in structure.  Maybe more so than any other typical backing wood.   That may be why it surprises people despite not being considered as "strong"   as   hickory.