Understanding wood fiber -theory.

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  • #27
thanks

I think quarter sawn will be strong vertically, but Euc cracks between rings. So may flat sawn and install so that it arches up and cups down
 
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  • #29
Thought it interesting how the tension side is a continuous run. I’m sure if you don’t make it that way, or you pull it the other way, it explodes. Like runout in an axe handle.

I’d like to try Osage for a handle. I have some I cut down, but I’m afraid it might have died and been desert dried for too many decades.
 
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  • #31
Light bulb on why the deep face prevents barberchair. Moves the transition or division point of rigid log.

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  • #32
Re: bending vs pulling hinge, I had a bulb on that one too.

Buckin went east and Humboldted some hardwoods. Fiber pull. The more closed Humboldt pulls fiber, where as an open or vertical hinge face bends and breaks the fibers before it closes.
 
I think there is a component of having the pith in the hinge.


"angiosperms (hardwoods) and gymnosperms (softwoods) build compensatory wood differently. Angiosperms produce tension wood on the upper side of a leaning stem, which contracts to pull it upright, while gymnosperms produce compression wood on the lower side to push it upright. These two types of reaction wood represent two different mechanisms for responding to gravity. "

With compensatory growth in an alder (local BC-prone species), there will be more tension wood, putting the pith close or within the hinge when face-cut shallowly.

If an alder is face-cut deeply, the pith will be in the front-side of the hinge and holding wood.
 
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As a general guideline we would teach that when you are constructing your hinge it should be a minimum length of 80% of the dbh and a maximum hinge thickness of 10% dbh. We called it the 80 plus /10 minus guideline. It's a good starting point for teaching new sawyers because it puts some measurable metrics when evaluating how they are doing.

There are obviously situations where you need to deviate from the "guideline" ... like putting in a deep undercut on a short stob for instance or dealing with side lean.

If you are getting fiber pull longer than 4 inches you probably should thin your hinge so it can bend easier. That's when local species knowledge comes in handy. Your Doug fir for instance should probably be a bit less than 10%.

Sorry Sean, I thought your question marks were directed at me, my bad.
 
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Osage Orange, a very interesting species.


One of the friends I've made here locally has the biggest and nicest I've seen in Mariposa County during my year of exploring trees here. I've been granted free access to the ranch, I just haven't taken advantage yet. He's a fine fellow, just queer as a two dollar bill and quite infatuated with me.
 
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