DDM
Addicted to ArboristSite
I'm going to purchase a couple of new rigging blocks Soon. I was wundering Which ones would be reccomended. I'll be using them on Fairly large wood. 
Rigging Blocks
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treeclimber165
Member A.K.A Skwerl
I bought the block in Sherrill's catalogue shown on page 22, item 'A'. Actually, I got the set that included a Tenex sling, listed on page 23 as items 'I' and 'J'.
DDM
Addicted to ArboristSite
That looks like a good combo Brian i was leaning more towards steel thal Cast aluminum.
treeclimber165
Member A.K.A Skwerl
I got mine about 6 years ago, gave it away a year ago after I had quit climbing (or so I thought). I had burned the sling once on a huge live oak when the bull rope slid across it with a 2000 lb chunk of wood attached. 
I had never done much rigging on huge wood except hooking it to a crane. Usually if it is that big you are rigging to pick up rather than let down. But this huge trunk was over a sidewalk and I was trying to get fancy. The good news is that I didn't crack the walk!
Back on topic, the steel block was very strong and I trusted it for as much weight as I wanted to cut at one time. It didn't have any signs of rust after 5 years and the pulley still spun freely. It is also the least expensive block in Sherrill's catalogue. I may buy another soon to replace the one I gave away.
I had never done much rigging on huge wood except hooking it to a crane. Usually if it is that big you are rigging to pick up rather than let down. But this huge trunk was over a sidewalk and I was trying to get fancy. The good news is that I didn't crack the walk!Back on topic, the steel block was very strong and I trusted it for as much weight as I wanted to cut at one time. It didn't have any signs of rust after 5 years and the pulley still spun freely. It is also the least expensive block in Sherrill's catalogue. I may buy another soon to replace the one I gave away.
i think i would jsut go with steel if i did it again. Don't use it that much, and the aluminum block isn't that much lighter (to me).
Eric E.
ArboristSite Operative
I have the Wall (steel) (cheaper) block and an older BGF aluminum block from before they made the spring loaded types. The BGF is by far the better block in friction and weight. There was a study done by Pete Donzelli on frictional properties of these two blocks and the Hobbs. Hobbs was the least friction then BGF and last was the steel block. The Hobbs block has the best bend ratio and largest cheek plates. Also the bigger $ sticker.
John Paul Sanborn
Above average climber
I got the yellow aluminum spring block. 4k lbs SWL , and having to do only a quarter turn to open them up is great.
Few of the 1K SWL CMI pullies too, use them with tenex loop slings and 30kn biners
Few of the 1K SWL CMI pullies too, use them with tenex loop slings and 30kn biners
DDM
Addicted to ArboristSite
Tuflex slings?
John Paul Sanborn
Above average climber
I donnt like tuflex except for realy big picks. I thing hollow brais for big jobs and web for every day stuff. If it is too big for the braid loops, then it is a bo'lin and a marl.
DDM
Addicted to ArboristSite
Ive got 4 or 5 Tuflex Slings i like them I'd rather use them than a Eye Sling.
I have a 3/4 Hobbs knock off , from Bailey's for $120 or so. then 5/8 stainless cmi's, nice and light. I will soon get one of the spring loaded ones, cool as the pin and sling sheave are spring loaded, so you can't drop 'em!!. Then an old steel 3/4block, still working fine, but heavier. And bunches of 5/8 and 1/2 inch pulleys, single and double. I may soon buy Oxman's heavy duty trolley block for speeding, like the inline sheave dubble petzl but much beefier.
Now making my own slings from Tenex, a bit soft and snaggy, but cheep!! Plus Tufflex, and oodles of 1 inch and 5/8 inch webbing slings.
Now making my own slings from Tenex, a bit soft and snaggy, but cheep!! Plus Tufflex, and oodles of 1 inch and 5/8 inch webbing slings.
treepreacher
ArboristSite Lurker
I use the same as 165 plus cmi's for lighter stuff redirects ect
tufflexloops are great splice my oun dbl braid dead eye sligs 1/2 in. to 3/4 in
tufflexloops are great splice my oun dbl braid dead eye sligs 1/2 in. to 3/4 in
Wow, inter-arresting numbers Erich!
i assume that was with all bushings and not bearings because of the loading, and that is with same diameter sheaves and axles in the tests?
The amount of leverage against the point of friction (bearings or bushing on axle), will be deteriminant to efficiency of device. So the diffrence between the sheave tread diameter and the axle diameter, determines the MA that the devce has on the friction point. The bushing/bearing on axle is determinat to efficiency too. Bearings are more efficient, but bushings take more abuse, much longer, but are less efficient in trade than the bearings. So these 2 things can arithmetically tilt things and override materials and manufacturing quality.
i do have a pulley with 5" tread on sheave (inner tread size actually supports the rope's belly, rather than the the outer sheave diameter) with bearings, zerk fitting SWL6tons, it is very efficient, and big! But does a 'silky' job of balleting and moving loads!
i assume that was with all bushings and not bearings because of the loading, and that is with same diameter sheaves and axles in the tests?
The amount of leverage against the point of friction (bearings or bushing on axle), will be deteriminant to efficiency of device. So the diffrence between the sheave tread diameter and the axle diameter, determines the MA that the devce has on the friction point. The bushing/bearing on axle is determinat to efficiency too. Bearings are more efficient, but bushings take more abuse, much longer, but are less efficient in trade than the bearings. So these 2 things can arithmetically tilt things and override materials and manufacturing quality.
i do have a pulley with 5" tread on sheave (inner tread size actually supports the rope's belly, rather than the the outer sheave diameter) with bearings, zerk fitting SWL6tons, it is very efficient, and big! But does a 'silky' job of balleting and moving loads!
Kevin
Addicted to ArboristSite
My best block has bearings, it was $400 and change.
I have an assortment of others from Sherrill.
I have an assortment of others from Sherrill.
John Paul Sanborn
Above average climber
Don't shockload that bearing block, they can deform much easier then bushing types and loose their efficiency (the berrings that is).
Kevin
Addicted to ArboristSite
Ok, thanks JP.
Kevin
Addicted to ArboristSite
What method(s) are used to prevent shock loading other than letting the object run a short distance while the groundman attempts to brake it?
If a heavy object falls even a short distance to a zip line the effects must be huge.
If a heavy object falls even a short distance to a zip line the effects must be huge.
Kevin,
Never drop heavy loads onto a pretensioned speed line. Either use a lowering line to ease the load on, or position the speedline above the load and lift it on.
The forces on the anchor can reach many times the weight of the load. And if a low or no stretch zip line is used, anchor breakage risk increases. A good reason to be careful, as well, to guy back the zip line
Never drop heavy loads onto a pretensioned speed line. Either use a lowering line to ease the load on, or position the speedline above the load and lift it on.
The forces on the anchor can reach many times the weight of the load. And if a low or no stretch zip line is used, anchor breakage risk increases. A good reason to be careful, as well, to guy back the zip line
i would go with pretightening the line,
wide smooth hinge,
slowing backcut as piece started to 'breathe' (show life, shift),
line over top, with guys flexing load slowly through hinge range;
to deliver as slowly and smoothly as possible to line on hinge,
then run line to matt of brush on the ground if possible,
allowing matt to 'snub' out remaining force. Or, running a de-accelerating load smoothly, but still in air, real good timing on groundie for that. Over a roof i do all this and then drew a tight stack of brush under to act as matt
To maximize when all that is called for.
Also i guess a "bouncier", longer line, would have more dampening action too
The line over the top can also double as a steering support for easily working face (placing block, cow hitch (girth w/half hitch), cutting kerf in sides to line up with backckut (to come through faster if i need to, fighting less material), lacing 1/2 hitch runnign bowline etc.
wide smooth hinge,
slowing backcut as piece started to 'breathe' (show life, shift),
line over top, with guys flexing load slowly through hinge range;
to deliver as slowly and smoothly as possible to line on hinge,
then run line to matt of brush on the ground if possible,
allowing matt to 'snub' out remaining force. Or, running a de-accelerating load smoothly, but still in air, real good timing on groundie for that. Over a roof i do all this and then drew a tight stack of brush under to act as matt
To maximize when all that is called for.
Also i guess a "bouncier", longer line, would have more dampening action too
The line over the top can also double as a steering support for easily working face (placing block, cow hitch (girth w/half hitch), cutting kerf in sides to line up with backckut (to come through faster if i need to, fighting less material), lacing 1/2 hitch runnign bowline etc.
Last edited:
Kevin
Addicted to ArboristSite
Good responses here, thanks.
Which is the best book(s) on rigging?
Which is the best book(s) on rigging?
