Barber Chair question

[northmanlogging]

not to be flipant .. but why don't you do you own research and answer you own questions.
then post it up for all to see ... there's nothing better than to see someone present a topic backed with actual evidence.

this topic has been around AS for quite sometime .. look how old this thread is
what's completely predictable was all the incoming crap .. ha ha ha

yup, typical moron response for "I don't know why don't you just give me the answers"

And yet every so often some newb shows up looking for answers, and some armchair lumberhack vomits forth with his "years's of wisdom" so newb goes out in the world tries said dumb ****, gets himself or someone else killed.... then a few years later rinse repeat, hammer the coffin nails home

 

[046]

yup, typical moron response for "I don't know why don't you just give me the answers"

And yet every so often some newb shows up looking for answers, and some armchair lumberhack vomits forth with his "years's of wisdom" so newb goes out in the world tries said dumb ****, gets himself or someone else killed.... then a few years later rinse repeat, hammer the coffin nails home

yet more name calling ..
why don't cha stick to what I actually stated vs making crap up that I didn't post
so now you are calling training videos put out by BC gov wrong .. ha ha ha

 

[ArtB]

Just might go outback today and see if there are any slight leaners left in my back yard (3 acres)
Will bore cut say a 8"-12" DBH alder WITH THE BAR VERTICAL, then a backcut with no notch.
Will do 3 tight wraps with a cheap 1" wide HF strap (and a few wraps of 3/8 HS chain loose above that fro safety).

Will be interesting experiment to see if the cheap HF strap breaks.

Just for added safety, night even position the bucket of my track loader a foot or so from the trunk at 20 ft up to catch it if the strap does break and chain too loose (which I doubt)

 

[ArtB]

Nothing like a test. Raining out here today, in mah old age to lazy to go cut a real treee in the rain, so resort to just break sticks.
3 wraps of cheap harbor freight electrical tape vs a strap. RH side clamped in a vise to simulate the trunk. Spruce is 3/4" wide, oak about 7/8" wide. Initial bandsaw cut simulates felling cut with NO felling notch for worst case barber chair simulation.
White oak and Engelmann spruce sticks, each cut from same board for consistency (oak is even the opposite ends of the same stick)
Probabaly could do this 50 times and the tape would always prevent barber chair.
Anyone really interested in the physics of forces could do this with sewing thread vs. tape and see how many wraps of thread it would take to prevent barber chair, in this test the electrical tape was only stretched enough to make a snug wrap.

 

[046]

Art .. Thank You Sir!

 

[rwoods]

not to be flipant .. but why don't you do you own research and answer you own questions.
then post it up for all to see ... there's nothing better than to see someone present a topic backed with actual evidence.

this topic has been around AS for quite sometime .. look how old this thread is
what's completely predictable was all the incoming crap .. ha ha ha

046,

You are the one proposing this technique. The purposes of my questions to you were twofold: 1) To find out out how you actually apply it; a fairly straight forward question. If you can't or won't demonstrate that then why should anyone take your advice on this subject. 2) To make you think. As long as some folks have been doing this and with the goal of BC and others to prevent deaths and injuries why haven't they endorsed this. And with all the gazillion gadgets and tools marketed to folks who cut trees, then why isn't there a purpose built strapping tool on the market. A pretty safe assumption is - because it is not a safe technique.

As to the experiment made, it only proves the theoretical. I don't believe anyone said it wasn't possible to prevent a barber chair with a strap (a big enough bolt, nut and washers could do the same). The experiment doesn't demonstrate the strength and snuggest required in real world conditions. I am sure an engineer could have calculate the results given the material, the size, etc. together with the composure and location of the strapping; but most of us aren't engineers. All the more reason to ask you to describe how you strap a small diameter tree. And how you decide which trees are suitable and which aren't.

Ron

 

[northmanlogging]

Nothing like a test. Raining out here today, in mah old age to lazy to go cut a real treee in the rain, so resort to just break sticks.
3 wraps of cheap harbor freight electrical tape vs a strap. RH side clamped in a vise to simulate the trunk. Spruce is 3/4" wide, oak about 7/8" wide. Initial bandsaw cut simulates felling cut with NO felling notch for worst case barber chair simulation.
White oak and Engelmann spruce sticks, each cut from same board for consistency (oak is even the opposite ends of the same stick)
Probabaly could do this 50 times and the tape would always prevent barber chair.
Anyone really interested in the physics of forces could do this with sewing thread vs. tape and see how many wraps of thread it would take to prevent barber chair, in this test the electrical tape was only stretched enough to make a snug wrap.


View attachment 790526

alright now restrain the other side with a stump and try it again.

what you don't seem to understand is that I have personally seen this fail, with real trees in real life.

I'll leave it at that, getting someone killed is on you bud

 

[ArtB]

For education, care to add any details on the personally seen fail ? Species, diameter, where backcut was, how much of a leaner, what type wrap broke?

FWIW2, only ever had one tree ( out of thousands) barber chair, 20 deg lean, bigleaf maple, about 15 inch diameter. Was well clear by the time it split and fell.
Have only ever chain wrapped 3 trees, all big black cottonwood. Not something worth doing 99.9% of time unless going to have to chain it up afterwards anyway to drag the log.
FWIW3, the test simulated a stump by having the RH portion in the pics clamped in a big vise.

 

[Bwildered]

The only B.S I have in in civil engineering.

I quantified what you’ve been arguing and proved you wrong. Now you don’t understand, and just call it ********. It’s not. You want to know how much force a tree hits the ground with? Weigh it. W=mg. F=ma. a in that case is gravity, g. So, that 75’ 12” cedar does hit the ground with 8,500 lb force. Which is greater than the force from the split. I’ll yield you that.

But your strap is still broken or up in the tree and you’re hurt or dead. At that point it doesn’t matter.

Now all you have to do is give us a simple diagram showing how the forces are transmitted to a strap at the butt of the log & overcoming the breaking resistance of it being 4 X its rated strength by being wrapped around the log, you are confusing the mechanics of holding the split together away from the fulcrum, the fulcrum being a point many meters up the tree. now if the split was reversed coming from the other end up the tree then force X Distance puts immense load on the strap, but that can't happen because a barber chair split doesn't happen that way.
While your at it you could give us a diagram showing how falling against the lean of gravity is possible too.

 

[Bwildered]

alright now restrain the other side with a stump and try it again.

what you don't seem to understand is that I have personally seen this fail, with real trees in real life.

I'll leave it at that, getting someone killed is on you bud

It's the same thing , just in a smaller scale, the RH side of the cut is the stump.
Tell us what you have personally seen & the details of it?

 

[catbuster]

Now all you have to do is give us a simple diagram showing how the forces are transmitted to a strap at the butt of the log & overcoming the breaking resistance of it being 4 X its rated strength by being wrapped around the log, you are confusing the mechanics of holding the split together away from the fulcrum, now if the split was reversed coming from the other end of the log then force X Distance puts immense load on the strap, but that can't happen because a barber chair split doesn't happen that way.
While your at it you could give us a diagram showing how falling against the lean of gravity is possible too.

I’ll get that up tomorrow... It’s too late to get out my stuff and draw it. That’s no joke, but I really think people here are confusing the failure plane and the direction the split causes force on the retaining tool, be it tape, a strap, a chain, whatever. But I’m assuming the split direction is perpendicular to the trunk, which is then perpendicular to the wide side of the strap. After the beginning the split is then at an angle to the remainder of the trunk.

Immediately after a split begins there is no moment caused by the split. Force in this case is equal to sigma times area. There’s where the 300 psi over whatever area gets the force. As it moves up a trunk, that moment increases and the reaction at the strap would increase if it were fastened where it could not move. I

I don’t get where you’re seeing me arguing a tree falls against the lean. But mass times gravitational acceleration is the same on the ground as it is in the air. The potential energy is different, but at the very small angle a tree has as it hits the ground a safe assumption is the cosine of the angle is one. That’s how you get the weight being equal to the force exerted on landing.

That’s assuming your restraining tool could be fastened tightly enough to not go flying when a barber chair occurs. Which isn’t possible by virtue of a chain binder or ratcheting mechanism on a ratchet strap not being able to follow the curvature of a tree’s trunk. That is my biggest problem with the test above. It’s not possible to strap or chain a tree that tightly in the real world. I hate to give any ground and argue against my fellow talented faller, but restraining both ends won’t change anything about those breaks.

And yes, extra wraps do increase capacity if they’re stacked on top of each other. So in our scenario at the point of failure with no moment, we get 12,000 lb or thereabouts. As an academic argument, okay, maybe. But it’s getting shock loaded as the strap can’t be tight enough to prevent all movement of the tree in the real world so the game is a little different and the peak amplitude goes way up even if it’s for a short duration.

 

[046]

strapped barber chair in action (www.youtube.com)

 

[Bwildered]

I’ll get that up tomorrow... It’s too late to get out my stuff and draw it. That’s no joke, but I really think people here are confusing the failure plane and the direction the split causes force on the retaining tool, be it tape, a strap, a chain, whatever. But I’m assuming the split direction is perpendicular to the trunk, which is then perpendicular to the wide side of the strap. After the beginning the split is then at an angle to the remainder of the trunk.

Immediately after a split begins there is no moment caused by the split. Force in this case is equal to sigma times area. There’s where the 300 psi over whatever area gets the force. As it moves up a trunk, that moment increases and the reaction at the strap would increase if it were fastened where it could not move. I

I don’t get where you’re seeing me arguing a tree falls against the lean. But mass times gravitational acceleration is the same on the ground as it is in the air. The potential energy is different, but at the very small angle a tree has as it hits the ground a safe assumption is the cosine of the angle is one. That’s how you get the weight being equal to the force exerted on landing.

That’s assuming your restraining tool could be fastened tightly enough to not go flying when a barber chair occurs. Which isn’t possible by virtue of a chain binder or ratcheting mechanism on a ratchet strap not being able to follow the curvature of a tree’s trunk. That is my biggest problem with the test above. It’s not possible to strap or chain a tree that tightly in the real world. I hate to give any ground and argue against my fellow talented faller, but restraining both ends won’t change anything about those breaks.

And yes, extra wraps do increase capacity if they’re stacked on top of each other. So in our scenario at the point of failure with no moment, we get 12,000 lb or thereabouts. As an academic argument, okay, maybe. But it’s getting shock loaded as the strap can’t be tight enough to prevent all movement of the tree in the real world so the game is a little different and the peak amplitude goes way up even if it’s for a short duration.

The same shock forces are in action whether the tree is strapped or not, if the forces at the butt of the tree were so immense, every tree would fly apart on falling and hitting the ground, trees that naturally barber chair are weak in the longitudinal plane, so easily split, if a split can be stopped from propagating as shown in the model demontration then the force of the binding doesn't have to be great, & once separated from the stump the butt of the tree would behave like any other tree & not fly to pieces.

 

[northmanlogging]

12" alder, 20 deg lean, climbing rope multiple wraps

36" cotton wood chain and binder

2" ratchet strap, 24" fir, hollow, not much lean

the alder cut the rope, the cotton wood stretched the chain to failure, fir tore the strap

 

[Bwildered]

12" alder, 20 deg lean, climbing rope multiple wraps

36" cotton wood chain and binder

2" ratchet strap, 24" fir, hollow, not much lean

the alder cut the rope, the cotton wood stretched the chain to failure, fir tore the strap

So in each case the wrapping failed to stop the barber chair before the tree came off the stump?

 

[ArtB]

I’ll get that up tomorrow... .

Will be interesting to see an analysis. To be accurate an analysis would need to be dynamic vs. just static forces with modulus of elasticity included in the equations and behavior in the yield region vs. using a simple break at yield.

 

[rwoods]

Bw, good to see the fires haven't run you over. I was thinking of you when I first posted on strapping here and the irony of our long running discussion of falling completely opposite the lean where I was arguing incremental falling in theory much like 046 asserting the theoretical here. Despite our failure to agree on incremental falling, I believe you understood my belief that in the real world falling completely opposite the lean rarely, if ever, intentionally happens when the actual load is with the perceived lean.

You seem to be safety conscious and knowledgeable of the forestry industry downunder, so let me ask. Do any of your regulators or trade associations approve of strapping to prevent barber chairs on small trees? Is this technique something you do, or recommend to inexperience cutters?

Ron

 

[rwoods]

strapped barber chair in action (www.youtube.com)

Bad link or a joke ????
RickRoll'D

Ron

 

[046]

Bad link or a joke ????
RickRoll'D

Ron

what do ya think ... ha ha ha

 

[rwoods]

what do ya think ... ha ha ha

I think I am done. You won’t take time to answer a simple question about a questionable technique you advocate as a safety measure for those who don’t cut much but instead take time to joke. Should we take it all as a joke?

Ron