Understanding wood fiber -theory.

davidwyby

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@gf beranek talks about understanding hinge fiber. I got to thinking about how wood splits more easily when split parallel to the growth rings (I think this might contribute to barber chairing on the back cut). Also about which way is desirable to have the grain in an axe handle. They are more flexible to the side, partially due to shape, and I think partially due to grain. Finally, about how logs are milled to produce boards with different grain patterns for different purposes/strengths.

1/3 of the way in, the cut is relatively parallel to the growth rings. I think wood fiber holds and bends more (or pulls and compresses more) when bent flat to the the layers/rings. If the hinge is in the center of the tree, the rings/layers are 90* to the hinge/bending direction and it seems to me would resist bending more and be more brittle.


Species, species, species....
 
Isn't splitting stubborn wood species dependent? I know stubborn locust will chip off fracturing on the ring surfaces. Problem is I can't remember if another species behaves with radial splits. Could it just be that a chord-cut is simply shorter/less wood surface to split than a diameter cut? But that ignores the separation along the ring boundary. Do videos of barber chairs show along-ring splitting or chord path - I think chord path.
 
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I still think the hinge is pushing and pulling more than bending, in some species at least. The hinge bends or holds until the front can’t compress any more and pulls the rear apart. Or the face closes. Therefore, a gap face allows more fiber on the front half to crush and bend. A triple hinge creates even more room for compression.
 
Wood bends. This involves tension and compression, i.e. pulling and pushing. This, both lines of thought are correct.

However...

Species introduces countless variables, then there is the variability of specimen. In the high altitude, arid environs of the mogollon rim, growth rings are typically tight, the trees a bit harder and more brittle than trees of the same species found elsewhere. Then there's the variability of urban trees. Has this tree been watered, does it receive more or less drainage due to the location of buildings or a leech field? Will it have the expected tight grain, or has this thing been watered and maintained for 50 years, making for a hard, dense core, and comparatively soft and pliable material for most of its bulk?

Thus, it's all theory, and the best part about a theory, is that it's never wrong. Experience establishes general guidelines, judgment acts with in them.
 
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