Block and Sling Size

[YUKON 659]

I was thinking of getting my first block and sling set up. Do you feel that a 5/8 block is large enough for most rigging applications? And is a 5/8 eye sling with 1/2 stable braid the right combo with the 5/8 block? I'd appreciate your input.

Thanks, Jeff

 

[treeman82]

Jeff, the 5/8" block and the 1/2" stable braid should work really well. However I thought they only make that stuff in 3/4, 5/8, and 9/16? Also, I think you want to get a bigger sling than 5/8" for a 5/8" block. I think you are going to want a 3/4" sling for that 5/8" block. But I could be wrong???

 

[TheTreeSpyder]

i think in new condition evenly matched numbers would be :

Block would be 2x line minimum,
Sling in single leg choke for block = 2.5xline minimum.

Looking for more wear in line, and lots of forgiveness/no wear in block, usually looking at ~2xline for block and attatchment i think.

i would still get the higher ten$ile line if i liked it. 5/8" sling handles my rigging needs, sometimes in a basket formation. i use 5/8" line for bigger stuff, not always with block. Most rigging is done with slightly used climbing line, to $ave back 5/8"SuperBr. and 1/2"kernmantle for more specialty stuff. @600#force per support leg, a 10:1 safety factor in 6k line. BlueStreak can do that trick to 800#+ force per support leg.

 

[YUKON 659]

TreeSpyder, when you refer to the 2x and the 2.5x line minimums are you refering to tensile strength?

Jeff

 

[YUKON 659]

Treeman82, pretty sure I saw 1/2 stable braid in the Wespurr catalog.

Jeff

 

[Tom Dunlap]

Get your copy of Arborist Equipment and read the chapter on rigging.

The other way to learn is to call Sherrill and you'll probably end up talking to the riggers or splicers to find a balanced system.

Read the Sherrill catalog about safety factors.

Tom

 

[TheTreeSpyder]

Yes, i was looking at tensile and 'assuming' arborist blocks, with sheave eyes.

The block/redirect from support system can take up to 2x line force depending on angle between support and control legs into block.

A sling in choke formation is usually calculated @80% of it's tensile, for block attatchment.

Mathematically methinx, that comes out @
IFF : (NeededSlingTensile x 80%) = (2 x SWL X MaxLineForce)
Then: (2 x SWL X MaxLineForce) x 2.5 = NeededSlingTensile
(Just as basket is 2.5x strength of choke lacing)

These are generalizations of mathematical patterns; no replace-meant for calling Sherrill; and getting model by model advice.


:alien:

 

[seanlarkin]

If you do decide to call us (Sherrill), and I hope you do, our number is 1-800-525-8873, and you'd probably want to talk to Johnny Carter at extension 231.
-Sean

 

[YUKON 659]

Sean, I did call today..not sure who I talked to but he was very helpful. I asked about a 5/8 CMI block with a 5/8 eye sling combo. He suggested the 3/4 block...probably a better choice. My thought is that the 5/8 block will handle anything we will be rigging at this point... I know our limitations!!!! Later on we can purchase more or larger blocks. Actually my son is my climber I'm just the ground "dude". I think I will be getting a 5/8 block...5/8 sling and use the 1/2 stable braid like I had originally thought...I just needed a little support.

Thanks, Jeff

 

[John Paul Sanborn]

My first block was a 2 ton spring block. I wanted something i could use in all situations. As I progresed i got a bunch of CMI steel pullies for most of the rigging i do today, leave the block for big wood.

Most of the time I hang a pully I use a CMI web slling or a Tenex spliced sling. 7/16 Tenex is around 900# tensil, and most of my regular rigging does not have any shock loading.

 

[take3wraps]

why not wait till santa brings one for xmas , he won't do you wrong like some catalog people !

 

[mikecross23]

About a month ago I bought a cmi 5/8" block and 5/8" x 10' sling and wish I had gotten 3/4" block and sling for use w/ 5/8" bull rope. When I started using these tools, I began taking larger pieces w/ more control and way more predictablility. I've only used my new gear a handfull of times but have already wished I would have bought bigger and longer slings and block after a huge water oak removal. I usually use 1/2" triple braid for most rigging though. Yer gonna love your new toys!

-Mike-

 

[NeTree]

Originally posted by take3wraps
why not wait till santa brings one for xmas , he won't do you wrong like some catalog people !

 

[seanlarkin]

I don't think I understand the insult/joke, but then again it's 1 in the morning and I'm starting to doze off.

-Sean

 

[mikecross23]

Originally posted by mikecross23
I usually use 1/2" triple braid for most rigging though.-Mike-

I meant 1/2" 3-strand rope, DOHHHHH!

-Mike-