rip cuts to reduce rigging forces

Daniel

Daniel

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If you look closely it appears that when this long limb starts dropping into the rigging, rather than shock loading the system, the slow reduction in leveraged weight reduces the weight on the rigging point, which moves up, NOT DOWN, upon release... When the piece releases it does load the rigging point lightly, but that's not much spring given the amount of weight and the length of the limb.

 
So now ripping cuts DO reduce loads?

Rigging down logs stance

Strapping the butt isn't something I ever felt necessary. YMMV If I were worried about a barber chair I might no rip the hinge. Another mitigation is to cut the corners of the face/apex/hinge If I could keep the top attached until it has invertedI'd be happy. Of course this now means that...
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Tom Dunlap said:
So now ripping cuts DO reduce loads?

Rigging down logs stance

Strapping the butt isn't something I ever felt necessary. YMMV If I were worried about a barber chair I might no rip the hinge. Another mitigation is to cut the corners of the face/apex/hinge If I could keep the top attached until it has invertedI'd be happy. Of course this now means that...
www.treebuzz.com
Click to expand...
your nonsense talk was about negative rigging... this isn't that... must have hurt your feelings though... sorry about that Tom. The truth can hurt, but it will set you free!
 
evo said:
That and the different faces cannot influence the speed of fall?
With negative rigging a slow fall can give the groundie time to choke up slack thus cutting the shock load nearly in half. Same as with dynamic overhead rigging, where the piece leans into the rigging line..
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Why post that video.. the description says the tall hinge holds better (against side lean)... there is no reference to the speed at impact... groundie choking up depends on the groundie skill and experience and lowering device.. I'd like to see the stats that shows how much it reduces loads... using a dynamic line (stretch in the line) and adding length of the line would seem to be a better strategy, depending on the above mentioned factors... NOTE if you're using the wratcheting winch on the GRCS to quickly take up slack, that is not designed to take shock loads... the static bollard is supposed to be used for shock loading, which is not easily used to quickly take up slack...
 
We call them peel cuts, standard stuff I thought. At least they were teaching them as an option when I was at college in 95.
Species dependent of course, but they are best when it hangs on a couple of fibres so there’s almost no shock through the system when you finish it.
 
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Daniel said:
Why post that video.. the description says the tall hinge holds better (against side lean)... there is no reference to the speed at impact... groundie choking up depends on the groundie skill and experience and lowering device.. I'd like to see the stats that shows how much it reduces loads... using a dynamic line (stretch in the line) and adding length of the line would seem to be a better strategy, depending on the above mentioned factors... NOTE if you're using the wratcheting winch on the GRCS to quickly take up slack, that is not designed to take shock loads... the static bollard is supposed to be used for shock loading, which is not easily used to quickly take up slack...
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Why? Because it’s very clear that this beautifully executed felling slowed the fall of the tree laying it down as gently as possible. Don’t trip on the side lean.
That is easily a $40-60k tree, western red cedar is a BRITTLE wood, easy to crack and devalue. Crack em enough times and your ass is packing.

Not unlike your silly peel cut slowing the fall into the rigging.

A Hobbs is rated, and can take slack. A GRCS winch can too, yet not advised but in the right hands it can and IS done many .

Obviously I’m dumbfounded I have to spell this out, no friction devise/simple hand held lowering. Some slack can be taken with a porty (just an half wrap) and not a close hauled sling using the sling angle deflection as a brake.

Ever have a top stop on the face? It’s not a fun experience. Imagine a 45degree conventional face, the COG moves slowly half the distance of horizontal thus the difference of dropping half the distance into the rigging. Do I need to remind you the simple napkin math? X2 per distance dropped?
 
evo said:
X2 per distance dropped?
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that's DOn Blair's formula and that is total; bullshit and misinformation... because it assumes a dead stop. When accounting for stretch in the line and using a dynamic line forces of drops up to 10'+ can be kept to 2-3x. That's with stretch in the line alone... not accounting for a controlled deceleration..
evo said:
, no friction devise/simple hand held lowering. Some slack can be taken with a porty (just an half wrap)
Click to expand...

if you can take slack up by hand without a friction device or a half wrap on a porty then there isn't enough force to make it matter..

you talk shot... but you're not even close
 
I like it when Daniel posts videos.

They get a justified 'thumbs down' on Youtube. LOL.

I have yet to see a single point made that wasn't common knowledge since before 1980.
 
Daniel said:
that's DOn Blair's formula and that is total; bullshit and misinformation... because it assumes a dead stop. When accounting for stretch in the line and using a dynamic line forces of drops up to 10'+ can be kept to 2-3x. That's with stretch in the line alone... not accounting for a controlled deceleration..
Click to expand...
Ha! I guess you have Blair to blame now for ‘misinformation’ and spreading bullshit by speaking simple physics.

Rigging forces don’t disappear, they get transferred.

Such as snubbing or letting it run, all the force is there. Where is that force going to go? That is the element we are trying to control. Speed and acceleration is a force that can be mitigated in the sawyers hands.

Choice of rigging setup and materials, sure!

Ultimately it’s up to the groundie and timing. Why not account for things that are in the sawyers control?
Daniel said:
if you can take slack up by hand without a friction device or a half wrap on a porty then there isn't enough force to make it matter..
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That there is utter bullshit. It makes a huge difference on marginal pieces. It allows for the limits to be pushed without a lowering device or with only a half wrap. Can’t see how you fail to see this.
Daniel said:
Why post that video.. the description says the tall hinge holds better (against side lean)... there is no reference to the speed at impact...
Click to expand...

Deflection at its finest, the description doesn’t say squat about side lean being the reason for the block face. The video shows a nice slow closure of the face, dampening forces saving out the log.
“With a box cut you get a lot more flex on the hinge before it breaks. This means you have control of the tree longer”
Daniel said:
you talk shot... but you're not even close
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Yet another personal jab, shit talking out of the side of your mouth. Oh Holy One, One with all the answers.

Post in thread 'Rigging down logs stance'
https://www.treebuzz.com/forum/threads/rigging-down-logs-stance.49107/post-757331

“bad advice Tom... that hinge isn't going to slow the speed of the piece down enough to make a differnce...”

Yet somehow when you advocate for it it’s gospel, when others do it you shit talk? WTF?
 
evo said:
Deflection at its finest, the description doesn’t say squat about side lean being the reason for the block face. The video shows a nice slow closure of the face, dampening forces saving out the log.
“With a box cut you get a lot more flex on the hinge before it breaks. This means you have control of the tree longer”
Click to expand...
Controlling the tree longer doesn't mean slowing it down.. idiot!
 
anyone that thinks Don Blair's formual is accurate as a practical guideline in assessing rigging forces in the field is misinformed..... It's not even close...


I did the experiment: this was with the lowering line locked off, so the stretch in the line alone took the forces down to 2-3x weight, when some of those pieces dropped 8-15'.

 
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