Limits of Hinge Performance

This video provides no tips on techniques. Rather, it provides an explanation of what happens to a hinge as a tree comes down. In particular, it looks at the limiting strain that the hinge can endure and how that affects its ability to resist side lean and to control the direction of fall.

[@spkay31]

I lost a good friend in a fatal felling accident some years back. As an engineer I never really studied the forces contributing to the actions of a hinge during the felling process. I really appreciate the level of detail you cover here. Too many people think felling trees is based on simple principles and common safety practices, but don't go quite deep enough to realize the many factors that should be considered.

[@iluvnikon]

Now i know what really happens and why. As with all in this series the presentation is outstanding. Thank you for all your hard work over the years.

[@terryhale9006]

Thanks Shutterbug!

[@rickmusa7482]

Absolutely fantastic job. great technical info, one of the best if not the best tree cutting videos on you tube, your efforts have undoubtedly saved lives and many injuries. this video should be mandatory before picking up a saw.Thank you so much for this effort.

[@wryipx]

LOVE THE PHYSICS ! Very well presented and put together! Thank you ! ... post critique is unfair, .. wedging, the forces, the reason (more than just preventing "sit back", more accurately aims tree fall, and adjusts for "errors" guessing center of gravity, etc), ... how a back cut not parallel to notch causes tree to rotate, and fall toward "thick" part of backcut. etc. .. Look up, look up.

[@johnrobertson7583]

I have seen quite a few of your videos. Thank you for your efforts to educate. Finally subscribed! Anyway, this technical description of the hinge failure due to various loads was awesome. I have been watching a another video channel called Finnish LumberJack, and when he cuts down the tree just before he makes the back cut he makes two vertical shave cuts about 1/2” thick along the edges of the hinge taking about 8 inches of wood away. I initially thought he was doing this to see the hinge better but now I understand he might be doing it to clear off the side fibers. He also uses two neat implements to aid falling. A crank powered extendable pole called a Stalpen, and a small Hand operated mini jack he made From two threaded rods...similar to a turnbuckle...but obviously used to push the ends apart.

[@chrisbloodshoofd]

Great information, that i've not seen anywhere else!

[@granjefetala]

Great exercise and great explanation. Clear and precise. Thank you.

[@terryhale9006]

Thank you, Pedro.

[@gabegoerzen3313]

Thank you for the video Terry! I love your application of mechanical elements to tree falling. I am a mechanical engineering student as well as a chainsaw operator who someday hopes to fall trees. I'm trying to learn as much as possible from many different sources to become well-rounded, thanks again for being one of those sources.

[@terryhale9006]

Thanks much, Gabe. (We'll exchange the secrete Engineer's Handshake later.) Best of luck with your continuing engineering studies and your future felling aspirations. I hope you eventually get the property to fulfill that dream.

[@_DMAC]

Your videos are a great help in understanding the theory behind what happens. Much more than cut a notch here, back cut there. I'm learning my way cutting firewood on the weekends for my own use, but have been educating myself as much as possible to be as safe as possible. Glad to have found and watched many of your videos. I find I understand things more from a mathematical and physics perspective in understanding not just how, but WHY. (Ie now I understand why I got my blade pinched on a very slight back leaner. Had to "pull" the tree against the back lean towards the felling direction.) Thanks for taking the time to really break down and explain the WHY!

[@terryhale9006]

Thanks, D. I hope you are enjoying that work or, at the very least, enjoying the results. Sounds like a great opportunity to gain expertise.

[@joshuacarroll7653]

Wow Terry! Thank you so much for taking the time to make and provide this very in depth video. There are many people that need to know this info both novice and professional chainsaw users. Well done informational videos like this doesn't only refine understanding of the complexities and many factors that should be know before attempting the felling of any tree but also in my opinion can save lives BECAUSE you deliver this info in a concise, well organized, and serious manor that is backed up with solid scientific explanations. Well done.

[@terryhale9006]

Thanks much Josh!

[@22skiddoo]

Fascinating - it's always interesting to know what's *really* going on behind the scenes. You evidently know your stuff and the maths takes no prisoners, but everything is so clearly explained it's almost impossible to watch one of your videos and not learn something useful. Thank you!

[@terryhale9006]

Thanks!

[@gregchaplin7188]

Great series. Thanks for putting all the effort into it.

[@robertogomez8036]

Amazing and helpful videos for those you really wanna know more about tree procedure jobs with knowledge cause being a tree climber or tree worker is a job you gotta take it seriously no mistakes allowed thanks Terry for making my work way easier.

[@andrewe2250]

damn it terry... i have yard work to do and I cannot stop watching these. I thought I was done 4 videos ago!

[@terryhale9006]

I'll sleep better knowing I have spared your grass for another day.

[@JacobGilkerson]

this is good stuff. Thank you for making the video. This is the science behind the original Humboldt which included vertically facing the front of the hinge wood. 👍

[@terryhale9006]

Thanks Jacob.

[@slimdusty6328]

Loving your informative videos. Thank you thank you thank you

[@terryhale9006]

Thank you very much, Slim!

[@slimdusty6328]

@@terryhale9006 honestly though Terry, straight up, its been like striking a gold mine of info . I have a fair few years of farm learned experience under my belt already ,however this info is most certainly valuable for anyone wanting to learn more 🙏👌👍

[@Garysopinion]

Not sure how I can use the info. What I have is a bunch of dead trees (re emerald ash borer). want them to remain vertical to dry until I need them for firewood. Now when the wind blows them over, I want them not to fall in one direction which is toward the house (they are not close). Another tree not to fall on driveway. I figure if the hinge is made perpendicular to the unwanted direction it should fall parallel to the unwanted direction. Not sure if I should just cut on either side of the tree with a straight cut or wedge cuts.? not sure if I explained that.

[@michedmck]

Terry! Congratulations on am extremely well-presented series, backed up by solid facts. I revisit your videos often, and frequently use them to show newcomers exactly how complex and tricky this felling business can be. I have noticed some anomalies regarding hingeing properties and would love to hear your input. I regularly help my brother-in-law clear out invasive Eucalyptus trees on his farm. The trees vary in diameter from less than 1 inch to around 8 inches. I invariably use an open-face notch on the larger ones (mainly for practicing accurate cuts for larger trees) with a 30% notch depth and 10% hinge thickness. In nearly every case I find that the hinge stays intact all the way to the ground. In fact, in around half the trees felled, the tree remains solidly connected to the stump via the hinge, requiring that I cut through the hinge to separate the two parts, before trimming the stump level and clean. Each time this happens I am reminded of this video, and wonder what is causing this phenomenon. Thus my question is: What factors are contributing to this? Could the American Forestry's 0.8% stretch factor be incorrect? Is the "youth" of these trees causing it? Could it species-specific? Can this effect be "scaled up" to be used on larger trees? I would be grateful for your input, and I am certain we could all learn something from it. Keep up the great work! Mike

[@terryhale9006]

Thanks, Mike! I appreciate you sharing that. I am not familiar with Eucalyptus. The species could certainly be a factor. You are also correct that younger trees tend to have a much higher percentage of sapwood and wood that has not hardened and mineralized into heartwood. I should have taken that into consideration when making the videos. I guess I had "big tree tunnel vision". The next time you have a hinge hold all the way to the ground on a 6 to 8 inch eucalyptus, see if you can tell whether the tension side stretched a lot or the compression side crushed. If you can tell, I'd appreciate knowing. - Thanks.

[@michedmck]

Terry Hale: Thanks for the prompt reply! I think you are spot-on - it sounds like the sapwood/hardwood scenario. I'm now nearly certain that the mineralized fibres have much less stretch than the younger, unmineralized ones. That is the key. I'll be sure to check next time, now that I know what to look for. I'll take some photos and send them to you. Regards. P.S. Eucalyptus is otherwise commonly known as Bluegum. We have around 80 species here in South Africa.

[@BusbyTreeSurgery]

i have been doing tree work arb. Climber for 30 years . There are a few times when hinges can stay intact, it can be used to your advantage we have cut pine trees down over paved areas . Trees of 45 foot high, probably no more. With 90 degree gob and hinge has stopped the tree from hitting the pavings . It is sledded up like this and then released from the stump. We also use this to advantage when felling on hills to keep tree and stump attached to stop rolling while the tree is snedded. These vids are top class but there as you have found certain species and hights and weight that will affect every thing . let's not talk about jump cutting haha.

[@t.p.2305]

Thank you very much!

[@Irishmacwoof]

Really good set of videos 2anys loggers on KZbin not talking about the basics

[@gordonpeden7432]

Thanks Terry, Love your work. Keep it up!

[@fsfltsurg704]

Excellent series. Great information!

[@terryhale9006]

Thanks!

[@AmosOHiggins]

Hi Terry. I was wondering about the effects of the 'step' on hinge performance. I was told, when felling, to raise the height of my backcut in order to create a taller step - supposedly this would allow the hinge to flex more before breaking. Having watched the video, I'm not sure about this. Can you shed some light? Cheers, Amos

[@soldtobediers]

This understanding done fired up a favored 40 year old cross connect. ''What ought'a make me feel old, sometimes makes me feel young again.'' -gilpin 122917 ''Oh, this old world keeps spinning round It's a wonder tall trees ain't layin' down'' -Neil Young ''Comes a Time'' (1978)

[@schnittteisen]

Soo good, thank you so much

[@tinadan308]

Another great video. Thank you.

[@terryhale9006]

Thanks!

[@philmoore71]

fascinating - esp as I got my repaired chainsaw back today ( a curious 'coincidence')

[@terryhale9006]

There's a certain sense of security you get from knowing you have a working chainsaw available. Welcome back to being whole.

[@hhoward14]

Thank you Terry...

[@dpeterbannister]

Excellent stuff there. Thanks

[@terryhale9006]

Means a lot coming from you.

[@michellepugh2859]

Does this stihl hold true if say a sizwheel is cut into the hinge for sidelean? Or a double or triple hinge is used? 1 of the most informative videos I've seen on the mechanics of falling.

[@Zlinky111]

Amazing Vid Terry. Loved it ❤👍😁 Since you are so good at the physics side of things, I mirror the comment by Michelle Pugh, I would really love for you to cover: Tapered hinges; The physics of those side sapwood cuts; The effects of different vertical cuts, such as double or triple hinges; The physics of the magical Sizwell.....and, the effects of combing these techniques. Also, is it true that the newer fibres near the bark are stronger than the centre ones? Re: the 80% rule, Some people do VERY deep notches, others VERY shallow. Sorry, so many questions, meant as a compliment to your knowledge. 👍😁

[@markeinarson1037]

Gr8 info Terry thank you

[@terryhale9006]

Thanks Mark.

[@9mmkahr]

This is what happens when an engineer buys a chainsaw 😆 just kidding, i LOVE your videos

[@cilicat]

I know this isn't recommended practice, but making the back-cut high above the notch will reduce the strain on the hinge and allow it to function through more of the falling arc? This would be at great cost to torsional stability? Fascinating stuff.

[@terryhale9006]

You're on the right track, but missing one detail. While cutting the backcut high would allow that side of the hinge to be tall (after the split propogated down), the apex of the notch controls the effective height of the hinge on the front side. If a vertical cut were made, running up from the apex of the notch, you should indeed have a tall hinge that would remain intact longer, guiding the tree in its fall. I actually tied this once, but things did not go well, due to the brittle dead pine. As wood gathering season is upon us again, I will try the experiment a few more times.

[@dpeterbannister]

Terry, how would you feel about my posting a link to this excellent 'lecture' on the Arbtalk forum.? Its predominantly UK based but there are notable contributors from around the world Best wishes Pete Bannister

[@terryhale9006]

I'd feel quite honored.

[@almypal8406]

1:35 Rats!

[@guss6469]

🔥🔥🔥🔥🤙

[@kaizoebara]

I'm still a fan of the videos - very good information! I assume your professional backround is with the forest industry?

[@terryhale9006]

I'm flattered by your assumption. Actually, I a Civil Engineer who, as a kid, wanted to be a Forest Ranger. I've always been interested in trees, even to the extreme of the occasional execution.

[@kaizoebara]

Well, good job then on applying your expertise to your hobby. Your scholarly approach is a welcome change from some of the other content on YT - I won't point fingers, but you know what I mean.

[@terryhale9006]

( YUP! )

[@loveyou-qk4bm]

any child could say what you saying by buying a book ,..you talk to much in each video ..

[@terryhale9006]

I'm not sure what point you're trying to make, but your several comments have made it obvious that you find my presentations annoying. I'm sorry if that is the case. You seem to object to having talking in the videos. If you are looking for action videos which have minimal educational value, you should look elsewhere.

[@thdebord]

Carlos Defreitas hope you read better than you can write.

[@soldtobediers]

Carlos; "Here's what i've found helps, when felt 'time threatend' from a deeper understanding of what mechanically is going on within any of The Creators' subjects..." -gilpin 122917 ''The less I was of who I was, the better I felt.'' -Leonard Cohen & ''The scientific nature of the ordinary man Is to go on out and do the best you can The fundamental story Of the contemporary man Is to walk away and someday understand'' -John Prine ''Vast are our pages left unfilled & unseen within Malachi 3:16" -gilpin 122917

[@Zlinky111]

I'll look out for you in 'Idiots with chainsaws' 37. 🤣