Sling attachment

the nice thing about a shackle is when you over load it the pin usually won't come out. with a hook it's all about measurements. one day this technique will fail. bottom line: there are better rigging techniques.
 
I would also be pretty worried about that set-up because of the risk that the loaded sling would shift the hook around and break the gate. Here's one way it could happen even if you 'dressed' the sling to the hook before the cut:

You rig a limb that has an upward curve to it in the middle. When the limb is cut it rotates 180 about its long axis as it reaches rotational equilibrium. During the rotation it releases the tension long enough on the sling and the sling shifts slightly, allowing the sling to move over the gate. (remember, the gate is upside down now...) Now you're in trouble.

No good saying that you wouldn't use this hook on an upward curving limb because sometimes a limb that doesn't look upward-curving will still not be in rotational equilibrium at the time of the cut. Also no good saying that you'll use two chokers, if you were doing that then you wouldn't be trying to save 3 seconds avoiding the time it takes to screw in a shackle.
 
sorry (drunk buzzing doesn't make for good positive comments so i edited the post).
 
Couple of things here. This is not something that I would consider a time saver and that is why I use it. That's irrelevant.

To come up with an exact scenario for this to "possibly" fail is reaching a little. Though it is possible, if I felt that concerned then I will switch it up.

With all due respect Norm I am far from denial. I don't think just any yahoo can use it. This isn't my first rodeo
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Those hooks were presented to me and I used them. They did a good job that day. I dont use them that much. Still like my clevis.

I believe those yellow hooks are rated around 45k. The cable on crane is rated around 40-50k. Winch pull of 10k. The sling for most of the cuts are 6.5k. Clevis at 3/4in wll 4.5t. Looks like sling is weakest point. Isn't that the rule for a rope rigged system? Is that any different?

Now on the A2B cable. I talked with the operator about it. He got tired of fixing/replacing so he removed it. According to him it is not required for inspection as long as the chart on crane is correct and can be easily read. Don't get on my case about the insp. part or osha regs for that size crane because I dont know. Im sure someone will let me know
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The operator is going to replace the cable with a radio version as soon as the tree market improves around here. The cost of the radio unit is $15,000.
Also, what did cranes do before the A2B. Were they unsafe to operate? By no means am I claiming to be an expert on cranes but, in tree work,whether you have A2B or not A2B(that is the question), your not going to know for sure if you overloaded until the piece is cut and held by crane.
It still comes down to the operator and cutter.

Ok i'm done for now.
 
"Now on the A2B cable. I talked with the operator about it. He got tired of fixing/replacing so he removed it. According to him it is not required for inspection as long as the chart on crane is correct and can be easily read. Don't get on my case about the insp. part or osha regs for that size crane because I dont know. Im sure someone will let me know
smirk.gif
The operator is going to replace the cable with a radio version as soon as the tree market improves around here. The cost of the radio unit is $15,000.
Also, what did cranes do before the A2B. Were they unsafe to operate?"

Tell him to contact CraneSmart. (www.rigsmart.com)Its more like 7 K for basic wireless anti-two block and wireless load cell/load readout. and down the road he can get the optional boom angle indicator/boom length/radius etc. I look forward now to jobs where in the past I'd have to fear the anti 2 block wire getting snagged, now I just blast on through (talking drivng up a low,tree lined driveway here, not operating).
Stop me if I told this before: but at the local Inkom cement plant, several years ago, they had a crane with an out of order ATB (not to be confused with a full blown load computer) and the operator two blocked it, whether by winching up to far and/or extending the boom doesn't matter. Anyway, he pulled the ball off (which fell and on the way down hit a guy in a man lift, who is now called Lefty (not really, we still call him Tod, but Tod now has one arm and one hook). I think of Tod everytime I see an out of operation ATB. If I had to chose between a rig with no load indicator or no ATB, and assuming the operator was experienced and the picks were of a known quantity, I'd rather do without the load indicator then the ATB, preferably of course neither.
I also think of a guy named Jim everytime I hook up an implement on my Kubota and am by the PTO: after 50 years of farming Jim felt a tug one day, and something then caught his eye about 30' away. It was his arm, pulled right off slick as snot. They sewed it back on and it works pretty well but it ain't the same of course. I'll never forget when I first asked him what had happened (I had noticed the arm was goofy looking), he looked me right in the eye and said "PTO". Nuff said....
 
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I would also be pretty worried about that set-up because of the risk that the loaded sling would shift the hook around and break the gate. Here's one way it could happen even if you 'dressed' the sling to the hook before the cut:

You rig a limb that has an upward curve to it in the middle. When the limb is cut it rotates 180 about its long axis as it reaches rotational equilibrium. During the rotation it releases the tension long enough on the sling and the sling shifts slightly, allowing the sling to move over the gate. (remember, the gate is upside down now...) Now you're in trouble.

No good saying that you wouldn't use this hook on an upward curving limb because sometimes a limb that doesn't look upward-curving will still not be in rotational equilibrium at the time of the cut. Also no good saying that you'll use two chokers, if you were doing that then you wouldn't be trying to save 3 seconds avoiding the time it takes to screw in a shackle.

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I understand your scenerio, but if you are only using a single sling when would it become unloaded.

before you even start cutting you should have the weight of the limb on the hook and all of the rigging so at no point does it ever become unloaded unless something reaches out grabs it and lift it off the hook.
 
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Where did you get those slings? I'm trying to find somebody who makes those round slings with hardware as part of the sling.

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I dont think the hardware is part of the sling. I use the yellow hooks but buy them seperate and add them to the system.
 
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