Looking For Experts in Rigging---just a tad off topic

**daveward** · 03-20-2013, 11:35 PM

The pictures are of a vintage snatch block I picked up and now have a perfect use for...except...
I don't know if this unit is intended to be used with a 3/8" winch steel cable line, which is what I want to do.
The markings on the unit show that it's a RIG 25 and 10" Snatch Block It also has the statement: "Max. Rope 3 1/2 CIRC." The actual diameter of the pulley is 6".

I'm hoping someone has some metal identification and or rigging experience and will say something like: "Nope, you dummy, the width of the pulley means it's for rope....or...."Yep, it'll handle steel cable". Thanks so much.

**BarrenRealms007** · 03-21-2013, 08:20 AM

As long as the cable will stay i the pully grove you will be ok. My concern it that the top loop looks like it has been broke and welded back and if that is the case this will be your weak link.

**toula** · 03-21-2013, 11:12 AM

Make sure you have the right size cable. If the cable is too small over time it will eat a channel into your pulley and cause it to fail. If the cable is too big it won't seat right and it will wear you cable out and cause it to fail under load. I would get different cables and see which one seats into the grove perfectly. It should be stamped somewhere on there the intended wire rope size. Hope this helps a little.

**daveward** · 03-21-2013, 12:15 PM

Originally Posted by BarrenRealms007

As long as the cable will stay i the pully grove you will be ok. My concern it that the top loop looks like it has been broke and welded back and if that is the case this will be your weak link.

"Barren...", you have an amazing eye for detail. I double-checked the welded part today and it's the first time I noticed the extent of the weld. You are perfectly correct. Thanks for the great catch.

EDIT: One thing I should have noted was another marking on the unit: "Max Rope 3 1/2 Circ." This confuses me a bit as it's not clear to me why this pulley would have any complete circles of rope. Hmmm...

Barren...thanks again.

**daveward** · 03-21-2013, 12:22 PM

Originally Posted by toula

Make sure you have the right size cable. If the cable is too small over time it will eat a channel into your pulley and cause it to fail. If the cable is too big it won't seat right and it will wear you cable out and cause it to fail under load. I would get different cables and see which one seats into the grove perfectly. It should be stamped somewhere on there the intended wire rope size. Hope this helps a little.

Like you, I assumed there would be a rope size marking, but I couldn't find one, hence this post. Your concern about a smaller cable eating into the pulley is exactly the issue. I'm having second thoughts. Thanks.

**toula** · 03-21-2013, 12:32 PM

Circ. = circumference

**daveward** · 03-21-2013, 12:52 PM

Originally Posted by toula

Circ. = circumference

OK...that's helpful. Let's say that CIRC is an abbreviation for Circumference. That makes the marking "Max Rope 3 1/2 Circ." even more obtuse to me. What do you think it's telling me? Thanks!

**toula** · 03-21-2013, 01:42 PM

It may mean that the largest diameter rope you can use is 3 1/2 inch.

**BarrenRealms007** · 03-21-2013, 02:03 PM

Originally Posted by toula

It may mean that the largest diameter rope you can use is 3 1/2 inch.

The diameter and the circumference are two different things. A 3-1/2" diamter rope would not fit in that pully, a rope with a cir. of 3-1/2" probably would.

**bejak** · 03-21-2013, 02:41 PM

3-1/2" circumference is about 1" diameter. If you do not plan on using check eBay sold listings for vintage pulley, cinch block, barn pulley or a combination of words that describes your item. You might be surprised at what some of that stuff sells for. The fancier or more unusual they are the more they sell for.

**daveward** · 03-21-2013, 02:45 PM

Originally Posted by BarrenRealms007

The diameter and the circumference are two different things. A 3-1/2" diamter rope would not fit in that pully, a rope with a cir. of 3-1/2" probably would.

Curiously...a circumference calculator suggests a rope with a circumference of 3.5" would have a diameter of 1.1140846016432 inches. To my eye the pulley is in fact designed for a rope very near 1". Interesting. Now...the key question again. If you have a steel pulley and use a steel cable of 3/8" is that going to grind away the pulley material or not?

**Libertytow** · 03-21-2013, 04:19 PM

when i was taught you use 1 /12th the sive of the sheav to determine rope sixe /wire rope anything smaller ruins the cable on any snatch block

**daveward** · 03-21-2013, 05:39 PM

Originally Posted by Libertytow

when i was taught you use 1 /12th the sive of the sheav to determine rope sixe /wire rope anything smaller ruins the cable on any snatch block

Thanks for the experience. Just so I am clear on the point you make, if the width of the sheave (pulley) is about 1" wide then the cable would be 1/12 of 1"? Or since the pulley is 6" in diameter the cable can be 1/12 of 6"? Thanks again!

**Bear** · 03-21-2013, 06:57 PM

I take it you're not familiar with "wire rope" ; ) It should also have a tons rating, possibly denoted with a T. Something like say 10T or similar, quite likely on the eye

**daveward** · 03-21-2013, 07:08 PM

Originally Posted by Bear

I take it you're not familiar with "wire rope" ; ) It should also have a tons rating, possibly denoted with a T. Something like say 10T or similar, quite likely on the eye

Bear...I don't understand why you would say I am not familiar with wire rope. The purpose of this thread is to determine whether I can use wire rope or not. I have been referring to it as steel cable. If that is a problem I am happy to call it wire rope.

**Bear** · 03-21-2013, 07:26 PM

you're on post number 15 and haven't called it that yet. Anyplace that works with it will note it as "wire rope". From most of the previous posts I actually couldn't tell if you were aware of it at all. It was no doubt scrapped because of the broken eye, which needs replaced

**Libertytow** · 03-21-2013, 08:09 PM

3/8" wire rope would need a 6" sheave if that helps

**SuperDave** · 03-22-2013, 09:15 AM

Probably would make a good clothesline

**Bear** · 03-22-2013, 01:15 PM

Dave, I really was in no way trying to knock you, or your post. It just didn't appear most of the posts on this thread were aware that the "rope" etched on the block would be referring to "wire rope", or cable, if you want to call it that, I think most everybody does(including myself). I was simply adding the thought that technically it is called wire rope, and likely what that message was about

**daveward** · 03-22-2013, 03:15 PM

Originally Posted by Bear

Dave, I really was in no way trying to knock you, or your post. It just didn't appear most of the posts on this thread were aware that the "rope" etched on the block would be referring to "wire rope", or cable, if you want to call it that, I think most everybody does(including myself). I was simply adding the thought that technically it is called wire rope, and likely what that message was about

Thank you Bear...I appreciate you post. You may have hit on the real issue. I am the one who needed confirmation that the "rope" etched on the block referred to wire rope or cable or whatever it is commonly called. I am the one who wanted to verify that the rope reference did not mean something like manila rope. I use the term wire rope and steel cable interchangeably.

Anyway...if you are confirming that the pulley I have is meant to be used with wire rope or steel cable, then you are the man...or...the Bear!

Thanks again.

Looking For Experts in Rigging---just a tad off topic

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