hinge wood dynamics

murphy4trees

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Per Jerry B's suggestion that there is no finer subject " in the trade to spark insights and opinion"

A careful study of this video gives some insight into the mechanics of the hinge wood when there is some height left to the fibers at the front of the hinge. I accomplish this by using the plate cut. Fundamentals mentions the block out face. I have seen tremendous advantage in greater holding ability of the hinge from the plate cut. If you look carefully at this video you can see the hinge fibers at the near corner of the face crush or fold a little early in the fall. It seems to me that having a little height to the hinge fibers allows the fibers in the front of the hinge some room to move. When the front of the hinge is allowd to sink or crush a little, it seems like that would spread the forces more evenly across the entire width of the hinge rather than concentrating the forces on the rear fibers and then just concertrating the forces on the rearmost fibers as the hinge tears. Much in the same way that the forces on a tight bend of rope will be concentrated on the outside of the bend.


<iframe width="560" height="315" src="https://www.youtube.com/embed/TtDWS9pFrVo" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
 
That's good video.

Can you shave the bark off, down to wood, to see what's happening at the hinge fibers? Too much hinge with too much force can be a problem. I like to see what's happening. Hemlock is not a barberchair-prone species, but we were pulling a tall tree, easy 150'+, away from a historic CCC kitchen shelter. It was heart-rotted, and we didn't want to lose the tree when winching it over-center. Pre-sena...too thick, too hard of a pull, and it started to split. He was way out of sight. I was cutting. I think I went in and back-cut it up a bit more, moving the force forward on the hinge, away from the splitting column of wood into new fibers. Went to the lay. No problem.
 
But then a good sharp chain rules over wood fiber.

Speaking of farwood, around 1958 my stepfather, John Wells, showed me and my brother Lee the basics of cutting farwood with a rik and cross-cut saw. From that day on Lee and I kept the house, and family, cozy warm with the farwood we bucked off that rik. John Wells was a good practical man and made sure to keep that saw nice and sharp for me and Lee.
 
I'v heard a bundle of firewood or farwood, as it may be, about 20" diameter being called a rik.

What do you call split wood that is close by? Firewood.
What do you call wood over yonder? Farwood. :lol:
 
I hear face-cords defined one row of the designated-length of wood. If it's 16" lengths, that's 1/3 of a cord, if stacked 4x4x8 to a cord. I've also heard it called a Rick of wood.

I made a saw-buck recently, for accumulated large limbs that didn't get chipped. Works a treat, either for woodstove cut-to-length or firepit sizes.
 
Nice slow mo'!
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i think at 'first folding' movement (that can cleanly continue on own) sets potential hinge strength.
>>you can let it ride it out or lessen hinge (parts) with saw, sometimes getting 'too happy' with saw.
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In usual fall/not back leaner , tree moves to a more leveraged position w/inertia also; into pre-set hinge/face support to close/tearoff nearer to horizontal..
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ANY loaded close is change in raw mechanix of load/pivot/hold positions, angles and distances between the 3 points.
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BUT, any purposeful close near vertical, can give artificial relief before the close, to force thicker hinge of same load with less support from front pushing back..
>>Tree moves to next position>>engages more support from front/close near vertical, lower speed of not throwing thru close/step etc.
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This gives the relief at first folding, then closes, like some Dutchman etc. changes pivot, support, angle, length to tension support IMMEDIATELY like pulse back thru machinery against impending loading.
>>If make normal face, and bypass the lower cut to come horizontally across fiber can get close/push from inline to fiber column.
>>But if double kerf down at back of hinge , can leave space of less support at start, to try to force more fibers in hinge>>then gap closes for more bolstering back as leveraged load increases instead of increasing load leverage and not support from point of 'first folding' of hinge strength setting per load being same in same situation, no matter what is coming next.
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Can draw later but to this imagery of behind the scenes/bark whereby close down strength of fiber column support pillars/stop command can be deadly at near vert.; but close across the fiber is just a type of bolstered flex we are doing at that angle across fiber anyway, just changing it some in the 'program' written into 'machinery code' before turning it on (empowering/enabling by removing some support):
hingeFiber_2_by-pass.png
 
An X shaped apparatus for cradling, holding, small logs so you can buck rounds off them. A rik a rack or something like that.

Ohhh... Gothcha. And thanks so much Sean for posting the Wiki page on "Sawbuck." Never knew why the Canadians called a $10 bill a "sawbuck," but I guess it's cause the X look of the thing put them in mind of the Roman numeral X. Learn something new every day, I tell ya's. Rick-a-rack-a-sawbuck. Give ya 10 bucks for it?
 
Believe it or not, this is just Aspen

20190527_092539.jpg

Enables her to pull wood hard on the tension side. Works a charm sometimes... less'n ya got stinkin branches runnin through yer hinge thwarting the whole process. :|:
 
We don't have aspen here, are you saying aspen doesn't tend to hinge well normally?
 
On the topic of creating hinges stronger than regular hinges, this is interesting but you may want to mute the audio

<iframe width="560" height="315" src="https://www.youtube.com/embed/gROnRUyWZmY" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
 
We don't have aspen here, are you saying aspen doesn't tend to hinge well normally?
Aspen is a poplar, so you don't get much control on it usually.
In my before arborist days, I cut a skinny one, about 70', front leaner, near the corner of a shed. My mother, father and daughter pulling on a rope to be sure. I putt a deep notch to keep the max of the side leverage for control and began the back cut. Just snap :O! even with a big third of the diameter not cut. My father fell on his ass, the aspen went where it wanted, barely missing the shed and landed on my trailer (I was stupidly too much confident to remove it previously). :whine:
After two days of steel shaping, the trailer looked much better, but it is actually still a bit crooked.:|:


Looks like the triple hinge of Logger Wade worked well this time. But I agree that his audio is often annoying.
 
We don't have aspen here, are you saying aspen doesn't tend to hinge well normally?

Was going to say same thing , not completely sure but very few places in New England get no Poplars (true weed trees , though they do have their place in Forest ecology). We have two here , Populus Tremuloides and Populas Alba. The latter had me in the guide book w a leaf after work.
 
Populus tremuloides is aspen, "tremble" in french. Both names latin and french come from the very mobile leafs in the wind, due to a long and flat leaf stalk.
 
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