vertical grain is stronger than horizontal grain

[dragonman]

Did you know that when the grain of the wood runs vertically through the limb of a bow,  the wood is stronger and more consistent than horizontal grain orientation? Differences in yearly growth rings are averaged out and the limb becomes more uniform than a limb with horizontal grain.
I was reading about experiments with early fibreglass and wood composite skis, which are made in the same way as bows and the wooden core was always made with vertical grain for added strength. The same technique is used in the core of japanese yumi bows too. My own experiments with ash self bows also agree. Vertical grain limbs take less set and pose less tillering problems, than bows with  horizontal growth rings.

what do you guys think about this???

[SLIMBOB]

Tim Baker in one of the TBB's wrote about this.  Not sure he said it was stronger, just that it matched a flat ring orientation strength wise.  Would be interesting to see data.

[Del the cat]

All fine and dandy if you have big diameter logs and a saw mill
But remember this is Primitive Archer, right?
Although to be fair it's the sort of thing I may try for a crossbow prod from some of my Yew offcuts, but I'm hardly gaing to saw up a Yew log to get it quartersawn and then have to laminate the sapwood back onto it... or am I???
Del

[BowEd]

There are all kinds of pluses and minuses making bows from edge grain or flat grain wood.Edge grain should always be more consistent the way I've seen it,but then a backing is needed in most cases.That's why your FG bow makers use that so much in there bows with their see through glass backing.Flat grain follows that ring on the back,and the grain feathers out on the belly.If both are tillered correctly to me there is not much diff in strength or durability.To me it's just a personal choice.Edge grain laminations to me opens up the power tools door with your drum sanders for thickness tapers etc.

[dragonman]

With  ash bows, they never need backing with vertical grain in the limbs. It doesnt appear to make the back vunerable.  cant see why it would be different with other woods that can be used for self bows...In fact , look at Half Eyes bows, they where always edge grain and usually not backed, he used many woods this way successfully

Del, have you heard of splitting?...,you need a hammer and a wedge, maybe an axe?...cant get more primitive than that.. actually even a handsaw is less primitive

[BowEd]

Yes I agree about clean ash or other clean grained woods,but if you got knots on the back like hedge,mulberry,or any wood with knots a backing is the safest IMHO.

[George Tsoukalas]

Of course, Dragonman. I'm glad you brought this up.  That's why the bowyer should ALWAYS follow the vertical or lateral grain when laying out a bow from logs EVEN if the staves were band sawed out of the log. If split the lateral grain will be followed. When making board bows the ideal is the have that lateral grain straight from tip to tip. If the board was milled at a left or right angle leave it there if severe. If the board was milled at an up or down angle, you'll also see the run off on the face and edge grain. Always that lateral grain should be followed. If you've built a bow from a small sapling you've followed that lateral grain automatically. The size of the log doesn't mean anything in that regard nor does  whether you are looking at boards.Perhaps people don't know what the lateral grain is. There's much more on my site which shows the lateral grain. Jawge
http://georgeandjoni.home.comcast.net/~georgeandjoni/layout.html

[dragonman]

George, thanks for the link to your website, I havent checked it out before. Lots of good info there, I've bookmarked it to read it all later.
Yes I think this important. Even with fairly small logs you can stil split them so that the vertical grain lines run from tip to tip along the back of the bow. Since I've been doing this, I find that the bows are much less prone to having one limb bend differently to the other. If I really pay attention to symetry, they often come aout almost tillered after the first stringing....which is ideal.

[LJB]

Interesting. 

Is edge grained wood, lets take Black Locust for example, less suspected to crysalling? Is it faster?

Leo

[dragonman]

Leo ,the only difference in performance would be that the same mass of wood ,would be slightly stiffer, so possibly very slightly faster... but it wont stop it crysalling

[George Tsoukalas]

Thanks, dragonman. Has nothing to do with the wood. Whatever the wood is that lateral grain has to be followed, SlimBob. BTW if you split out your staves from a log as opposed to band sawing them out, you have automatically followed that lateral grain. The term flat grained or  plain sawn, bias grain or rift sawn, or 1/4 sawn or edge grained refer to the type of the board cut that you can find at a lumberyard. They'll all make bows provided that lateral or vertical grain is straight tip to tip. Jawge

[SLIMBOB]

  How did I get dragged into this?

[Artus]

Hello guys!

I came across this old thread and found it really interesting. So I dig it out with a question:

I‘d like to use a small ash log, split it in half and use the splitting surface (the side that is normally used as belly) for the back. The fibers would be intact, just as with a chased ring at least from what I understand.
I can see some advantages here: Wide limbs can be produced even from small logs, because there is no high crown. The cross section is rectanguar and it accelerates the roughing out.

Has anybody expiriences with this? If it works, why is this technique not as common as chasing a ring?

Thanks!

[bassman]

Just made an edge grain Black Locust bow out of a questionable piece of wood for a bow.The growth rings were paper thin.So instead of chasing a ring I made it edge grain. It worked fine, but had some horizontal knots running the width of bow on the back.I shot it for about 30 shots that way, and it held up.Opinion on primitive said it was dangerous. Really liked the way it shot so I backed it, and wrapped the knots.Still shooting.I have also made hickory bows from clean one, and a half by one and half inch Amish wagon wheel blanks that are doing fine.Sudbury design.If the blank has thin growth rings I think edge grain is the way to go with certain woods that are knot free blanks.JMHO

[Scyth]

The identical piece of wood -

Vertical Grain favors compression tension
 
Horizontal Grain favors elastic tension

(. . . pick your poison . . . )


regards,

John