First Fexxing of Hinge

[TheTreeSpyder]

i think that a hinge's strength is set at it's FirstFlexxing; usually a second or so in the first movement. Pulls, Pushes and Cuts after that serve to weaken/speed the machine of the hinge, from slow/powerful setting of the machine powered by the C.o.B. falling IMLHO. Felling just with lean as power (no line or wedge) forces a hinge strength equal to the leverage of lean at FirstFolding (when no more cut is taken); but then in falling gains speed and more lean, to tax the strength of the hinge, that has been preset earlier. If at the FirstFolding, we 'fake' out the hinge with extra push(wedge) or pull (line), to make Nature 'think' the tree is heavier at FirstFolding than it is; then She will respond and match with a stronger hinge as equal and opposite reaction; that gives more support to the hinge to handle better the increasing forces of speed and leverage loading as the tree falls. A wide FaceCut with no dutchmans (with some exception...)taking the fullest advantage of this support offered.

i think that wedging is good in that it applies MA and arching leverages until movement ensues, then backs off (pressure is reduced as tree lifts to arc forward on the hinge). A rope can give high leverage quickly, but can be pulled too long too, making weaker hinge, pulling after the first flexing..

All the line pull before the tree is ready to go (that doesn't hold against backlean) is kinda a waste outside the preset to have force ready at FirstFolding. If you were to impact all that at jsut the right point and then back off; it would be at FirstFolding to force the strongest hinge. With a wide FaceCut, no Dutch, high wood strenght and flexability between this FirstFolding can force such a high strength hinge, the hinge fights you all the way to the ground pivoting on the hinge as you pull, connected all the way.

In rigging especially, i find forcing a more supporting hinge helpfull; especially as it only needs force at a certain small window of time to do so. i find forcing a stronger hinge in tandem with a tight supporting line to give superior strength and security.

Impacting at the right moment with high pressure to force a high strength hinge, with simple tools and settings in place is something that leveraging a tight line by bending does and lends itself to with key ingredients of high leverage for a short distance, to force quickly a super strong hinge at the right moment.

 

[Kevin]

All based on a good hinge but what about those punky hinges where the only good wood is the sap wood.
I posted this on the FF a while back but it's a good indicator before you commit to making that back cut.
Read the wood in the notch and it will tell you how much control the hinge will have.

The Notch

 

[Tom Dunlap]

Kevin,

In that case would a plunge cut been a good choice? Being able to slip in a wedge or two could add a little lift. Those are scary falls.

Good looking pup? Does Jessie work with you all the time?

I like your log arch with double ended skis, very clever. Do you add wheels for mud season?

Tom

 

[TheTreeSpyder]

Nice pics!

i try to look at a mix of felling and climber's rigging as 1 general science; still trying at this point to trace the deep set, binding factors. Look for a matching lesson in one as i learn in the other.

In rigging to make up for wood strength/flexability i might pull back into the hinge with line angle, to place the job of stretched fiber to maintain compression into the hinge on the rope fiber and not weaker or less flexible wood fiber in hinge. Done lightly right horizontal sweeps into the clear can kinda pivot around veritabley on a 'ball and open socket' needing just the pressure into the faces, not so much strength and flexability of fibers.

In a case like felling, if the outer wood in hinge was going to give more strength and flexability than inner heart so bad etc. i might try as i saw Soren Erikkson did in a tape and cut some of the center wood out of hinge by horizontally plunging the hinge through the center of the face.. Eliminating wood that would take efforts/forces to flex, but would not give desired strength/flexability on hinging in return for increasing their numbers. Thereby after center punching forcing the folding of hinge fibers with more pressure, looking for that stronger matching response, and not 'wasting' the effort bending ones that won't yield support(Sounded good anyway!). It has been booed by some, but has worked for me. i think that there is something about not weakening the block of hinge opposite the lean to much this way against sideward pulls, when ushering a sideleaner straight with this.

And sure, that might not be best either(hope i even understood ya right!), every job is different, i just trying to chase out the consistent patterns to see where to apply the most i can easily and when; kinda find it a fascinating puzzle!

edit, swooped by Tom's pen again!

 

[Kevin]

Tom;
A plunge cut is a very useful tool to have, I use it primarily to take the stress out of leaners.
You can see the sapwood is missing on the hemlock due to skidder damage many years ago.
That has an adverse affect on what the hinge will do.
I had to turn that tree so it worked out with the good holding wood missing on that side.
The saw dawg is a good companion and loves to go with me.
When I start the saw he backs out and lays down until the tree is on the ground, funny he has the smarts to do that!
I try not to skid in the mud because it's hard on the band blades but the axles will take wheels.
Many times we cut a notch, make the perfect back cut only to have the tree fall somewhere we didn't intend and that's the reason for the picture.
The wood tells the story and it is an indicator we should take advantage of.
When you take the notch out of a tree and see that the inside is punky you know the hinge will fail early and it might be a good idea to get some wedges in there for support.
Just something else to consider.

 

[Kevin]

If you select "normal size" on this picture you can see the punky hinge on the birch stump.
This is a candidate for breaking early.

Punky Hinges

 

[TheTreeSpyder]

Dont Pay for Non-Supporting Fibers!

Sure does, gotta work with what ya got! Here is kinda to previous question, and partially what i see in this.