Dent on Hinging

[TheTreeSpyder]

i would kinda say that is how you measure strength, what portent of it you needed.

That funny made hinge provides more strength of pull to the off balance load in the opposing corner, more than that of a normal 'strip' that i imagine you mean when you say rectangle. So in fighting that load, it is strongest, for the fibre at tear off is scheduled at the most leveraged position to fight that sideways pull on the hinge.

But in there, there would be less fibres slightly, because the ones all piled in one corner, mean fibres more in back bending and flexing over other ones in front, so more resistant to flexing, so equivalent force pulling on them would leave less fibre in that hinge than a strip slightly. So in that sense, that application you would be right, so you can choose wichever hinge's proerties to suit your task.

i think that like 'forcing' a plant to have more shoots by challenging it, the way to get the strongest hinge is to force it to flex early, so tree comes forward with more fibre holding it. This can be from a rope, wedge etc. That will leave the most amount of controlling fibre, all with the same strength per.

One reason to use and be aware of all this in the tree, is to make things pull away from ya slightly, or go right between some branches, or lay into/pre-stretch a rig. Just realizing you can dial that hinge in for diffrent applications is a serious empowermeant.

 

[Kneejerk Bombas]

Kevin, support your statement, with a specific example, of how a different shaped hinge would be stronger and therefore better than a rectangle.

I hope you defend the Mickey Mouse hinge...

 

[DDM]

Spyder? Are you putting these principles into application? I dont mean in an open field I'm speaking of on a customers property with a limit for error?

 

[Kneejerk Bombas]

That funny made hinge provides more strength of pull to the off balance load in the opposing corner, more than that of a normal 'strip'

No it does not. A rectangle is stronger.
I think I can prove it too.

 

[Kevin]

Swinging a tree, bore cutting the hinge to prevent splitting, those are just two very basic examples.

 

[Kneejerk Bombas]

What is swinging a tree?

I was afraid bore cutting a hinge, to preserve the ends of the log for the best lumber would come up( to muddy the waters), but that has nothing to do with the strongest hinge.

 

[Kevin]

I am suggesting we talk about the hinge first. I'm suggesting we talk about the

I was making reference to one portion of your question.

The strongest hinge would be no hinge at all.
The larger the hinge the stronger the hinge but why would you want to waste my time discussing that?

This is swinging a tree, ...

 

[DDM]

looks like a short speed line

 

[Kevin]

I never thought I would have the opportunity to use that picture again!

 

[TheTreeSpyder]

For years i have used these principles in every rigging, felling and limbing cut. Dent used them, only he was more logging valuable wood, so he did all this on the immense logging scale, and put it to that test. Every examination seems to flow with this line of logic he presents, so i rest easy with it.

Another hinge strength note would be, to place facecut right before center of tree some, where you would have the most length of strip across the face with least amount of rear fibres flexing over forward ones (making there flexing more reisistant) at tear off there by, taking fewer of them to finally fail/fold than if they didn't flex over each other as much in a longer strip.

There are also things about softer landings to be considered here. But i guess later! Each fibre has so much strength, and jsut like a specific hitchpoint in rigging, diffrent points of pull will yield diffrent properties.

Refrences to holding wood on one side of the hinge is spoken and warned of in ACRT, "Fund. of General Tree Work" (Beranek- from 7' diameter @150' up poster), and in Dent's book, that i think really discusses hinges mostly and more than any other.

This stuff really, really works, it is mechanically sound. Fibers of equal strength aligned to one side will pull more to that side, if they have to flex over their brothers in the front rows, they are even more torquing to their side.

My MM hinge (why would anyone with those initials refer to anything as Mickey Mouse in front of a sarc-ass-tick lil'MF'er like me i'll never no!!! ), is actually simple compared to some of the models in Dent's book! i really respect Mr. Mike for getting a handsaw he didn't beleive in to test, above and beyond the call, and very open minded. i use a handsaw for final release in air, really get some slow tips to the rig then, i try to capture in those few slower moments, what is going on, it all backs this stuff up. These things can be practiced/observed on 1-2" limbs on up with a hand saw for face and back cut, i think you'll find that triangle will pull to the side, sometimes balancing the pull of off balance end.

 

[murphy4trees]

MM,
I appreciate the info on a triangular hinge being strong. Geometrically the triangle is probably the "strongest" form. And for the hinge to direct the fall well, is it necessary to cut the rear corner making the actual holding wood more "tetrahedronical"?

Is the strongest hinge always the best? Answer "it all depends".
On what? On what you design the hinge to do. Which is...
Too much to mention here.
I believe loggers now are taught to plunge cause it adds seconds to their escape, and prevents barber chairing.
What if the tree is twice as wide as the bar?
What if there is no room for error in the lay?

RB,

We don't get paid much for wood out here. So not cracking the chunks is rarely an issue. Though getting them to land in the box often is and controlling tumble can help with that. I wonder if it would be possible to create a chart or formula with length of chunk, width of notch, and hieght of fall variables yielding amount of rotation?

Spidy,
Is wood preservation why you use a narrow notch when topping? I wouldn't expect you to be getting paid much for wood down in Fla.
And thanks again for the thought provoking info. I pulled out Dent's book and reread quite a bit with more blood flowing to my brain than usual. I Am going to think some more and do some experimentation in the field. Your passion to understang the workings of the machine we call a hinge is inspiring. Thanks

I really get turned on by using creativity and knowledge to get the tree on the ground faster, safer and eaqsier than the next guy. Notches and felling technique can play a big part in that. It takes confidence that can be aquired from that passion to understand and observation.

God Bless All,
Daniel

 

[TheTreeSpyder]

Not sure strength of geometric arraingement is write on hear.......

ummmm more to simple fiber count to one side pulling more where there is more of exact alike fibres, as sumnation of total pulls to any point.

and fibres placement (front to back) as a measure of its individual resistance (pull) in that position, all fibres being alike; rear ones flexing over the front ones stretch more. Or reaching across the axis! Hmmm like the front of the hinge is the pivot, anything out back from there moves across a greater diameter of sweep. So anyway, with same force against hinge's holding wood, there would be less fibre, pulling more for it has the same load pulling when it gives! When we make triangle hinge, there are more fibres to the rear. So more fibres are stronger, so strip is right, but, then; we have fewer fibres strategically placed that are working harder on a same task (in off balance head), so that could be greater per circumstance!

So MM would be right about it being stronger, we are just working them harder, by their place-meant. So if you have an off balance situation, do you always get the strongest guys, or the hardest working?:Monkey:

 

[Kneejerk Bombas]

I said I was here to defend a position so...

Daniel wrote:
"Geometrically the triangle is probably the "strongest" form. "

Not for a hinge. A rectangle is strongest. If you want to steer the wood a different direction, change the angle the rectangle faces.

"Is the strongest hinge always the best? Answer "it all depends".
On what? On what you design the hinge to do. Which is..."

Steer the tree to the lay. So yes, strong is good. An exception may be saving the lumber from harm.

"I believe loggers now are taught to plunge cause it adds seconds to their escape, and prevents barber chairing. "

And several other things, but we are discussing hinge shapes, not backcuts.

"What if the tree is twice as wide as the bar?"

That does not change the physics of the hinge.

"What if there is no room for error in the lay?"

That's what we are discussing. What are you a logger?

Spyder, I have to digest your post for a while.

 

[murphy4trees]

Spidy,
You said " simple fiber count to one side pulling more ".
I always thought it was more than simple fiber count on one side changing the direction of fall. I thought it is the angle of the backcut, such that the direction of fall will tend to move towards a direction perpendicular to the line of holding wood along the rear of the hinge, thus perpendicular to the bar during a backcut. When line of front of holding wood and line of back of holding wood are not parrallel, there are opposing forces, each trying to make the hinge fold in a direction perpendicular to itself. It also makes sense that the holding wood on the back has a greater effect as it has to move more, yet that has not been my experince in the field.
So back to the question. Is it simply fiber count or does angle of backcut create the effect?
And what about my other question???
God Bless,
Daniel

 

[TheTreeSpyder]

i think it is the arraingement of fibre while hinge is moving until the faces meet or something else gives that steers. That, is witnessable forensically as torn fibre arraingement on stump/ spar base mostly. When you look hard and have worked these principles hard, you can see the more stretched fibres in these positions when tested so when you check the stump after felling, while all is still fresh in your mind. You get a nice one, with that triangle of torn fibre ushering an off balance load, and you can see the fibres more stretched from the rear, and witness what they have done (workwise). i think the perpendicular image worx, because the most torqued fibre on the R hinge, resists being pulled straight out of the tree, and settles for forward or back, as rest of hinge is folding there. Whereby, the front hinge fibre is the pivot, as fibre moves back from that pivot, it gains more leverage, like anything else. The cross axis is the most 'obtuse' pull, tensing the opposite fibres more than any of the others. Just as in ropes, the tighter fibres are carrying the load, doing the work. We are forcing this in these placements; and giving them large enough numbers for the work. they must do.

The bar can be at almost any point at release, in hinge, just severing that last fibre to fail/fholde........ Now if ya hang around, you could probably use the moving force, adjust the hinge fibre even more, through the sweep, but that would be staying near the stump during all that, so , um ruled out, of course in the tree it has to fall away from ya if you are over it, so it is safer to do that!

i have oversteered a tree with the triangle on one side pulling the tree past the vortex, gunned point of the hinge/facecut. Dent in "Pro Timber Falling" said it was mechanically correct to lay the tree in the gunned sight, to cut your facecut to do that, then use the holding fibre to adjust for the head weight. So i have taken his word on laying it straight off the hinge, kinda makes more sense to set it square as i think about it.

i think the fibres will want to be lazy and lay the tree where it requires the least flexing of the hinge fibres. If the tree pulls Left, the right hinge fibres are the most confronted, piling them up, give 'em the strength and torque for the load by their numbers and position being altered. There are more of them by count, flexing more by position. These are the only 2 ways to effect that steering (side strength), and this employs them. To multiply that effect, we pull the tree into the face earlier than it would naturally. So it starts to fold with more fibre in the hinge, accentuating those characteristics we speak of putting into the hinge. This also gives more control over speed, wider face uses all this through a wider sweep, wider part of the stump for the hinge gives a wider strip of hinge to play with and more higher leveraged positioning (farther from center) available for fighting the cross axis (which is name i think i put on it, as i tried to understand it).

Murph i think this answers your question: from skinny pines post-

"Looking to minimze 'air ride' in the convertible by letting top fly away before 1:30 on the clock, sending the resultant kick back down the spar through strongest axis(every action will have an opposite and equal re-action), rather than letting it go further (2:00-3:00)and it pushing or pulling on spar horizontally, at its weakest axis. Looking to get a clean immediate tearoff/fly a-weigh on topping, a bending over and serving to line with least shock in rigging generally."

Rog, do you let the faces close in that topping cut? i visualized not, thereby assumed it was pairallel to this, being narrow->not closing->early release.

i think the strongest hinge has the widest strip, and is forced to work with more fibre (earlier). The one that works the hardest, is the one that is torquing the fibres most under load. The wider strip gives the most leveraged positioning for this, and undermines the tree's center of balance more too.

 

[Kneejerk Bombas]

I don't think anyone wants to argue that a rectangle is the strongest hinge shape. To steer a log, aim the face cut the direction you want to lay the log, compensate for lean.

Murphy wrote:
"When line of front of holding wood and line of back of holding wood are not parrallel, there are opposing forces, each trying to make the hinge fold in a direction perpendicular to itself. "

That's why a triangular hinge is weak. These two lines Murphy speaks of, being paralell, create a rectangle.

Why talk about triangle hinges?
The oh **** factor. Once a tree starts to fall, and you see it's not on target, you can release some holding wood on one side(create a triangle shaped hinge) as it's falling and get it to change direction. I can't imagine setting up a tree with a triangle hinge though.

 

[rbtree]

Mike,

there are two different "triangle cuts" in your example.

B is used as an alternative to plunge cutting for head leaners, to eliminate barber chair. I use it a lot, especially in the tree when there is not room to properly set up a plunge cut.

C "triangle" shaped hinge can be used to turn the falling log, and the decision to use it can be made at the last minute to bring the fall into the desired lay. Say, for instance, with any tree, regardless of lean, if any, but to fine tune the fall. None of us is perfect every time, as well, the tree doesnt always go exactly where it is gunned.

I do agree with you, that a rectangular hinge can be used with pull and wedges to bring a tree into the desired lay, and is plenty strong.

However, here is a real life example of working against lean.

At Arbormaster in Seattle 16 months ago, Rip Tompkins demonstated falling a severe side leaner with quite a bit of back lean. His plan was to do it with wedges only. He allowed us to set a pull line as a safety backup. He estimated the segments in the tree, which told him he would need to stack wedges, maybe three high, I dont remember for sure.

He gunned the tree to a spot about 2-4 feet right of where he expected it to fall, and opposite the lean. In other words, he did not expect the holding wood to hold on totally. I guessed that the tree would fall even further away from the gunned spot. It did. But he got it, with wedge use only. I was very impressed. I really don't remember whether he used more holding wood on one side or not. But he did use the plunge cut to set up a strap. Personally, I can not see using that technique for other than head leaners. I agree that it is is safer, as you can cut the strap and run. But, in presetting the hinge size, too small will result in the hinge wood not holding, too large means you have to finish it off after cutting the strap. The latter is what happened if I recall.

The tree had some decay, so the wood's holding power was diminished, as well, big leaf maple is not the strongest. In our area, the appx. order would be, weak to strong: cottonwood, alder, maple, hemlock, fir.

spyderman,

The hinge definitely closes early when I'm trying to control the spin rate of a log or a top with brush on. Quite effective at helping a (brush on) top land flat. Less and less effective as log size increases. Best used with straight grain, vertical wood, as I've said, and requires severing most of the hinge as the log is falling, so control is diminished. There will be more stem movement caused by the early closure, and the remote possibility of the piece coming back off the hinge. So, a humboldt and stepped up backcut is useful.

With wood under about 10 inches, the easiest method of controlling spin rate is to grab the butt and hold it back or push it down as it is breaking off the stump. Naturally, one must watch where his hands are placed, not in the closing face as I once did with a smaller log. i just caught a bit of flesh, but it didnt feel all that good.....!

 

[TheTreeSpyder]

Along the way, i have made notches in 2" diameter vertical stuff etc. with chain or hand saw, sometimes with a 'triangle' hinge, then finished with a backcut with handsaw eliminating a lil fibre at a time, walking it to the point of failure/fold gently.

All this as i am pulling or pushing branch myself. This slow motion examination of these principles, as i form folding and pulling/pushing, has done nothing but bare these things out. Sometimes i pull from a sling thrown higher than i can reach, for better leverage. i have learned alot doing that. Perhaps i can offer that easy to obseve field test.........

Another assumption i have made Rog, is that 'spin' is meant as flipping end over end?

Mike, a rectangular hinge means a strip from side to side across the face? Not just any rectangle or square fibre in any posistion?

 

[Kevin]

Mike, when a tree starts to fall get the hell away from it.

 

[TheTreeSpyder]

This shows the delivery of a tree to the balance of pulls.