7P Recovery Ring

I would think that a delrin, or HDPE/UHMW collar would be better as a slip material than a coating. at least it could be replaced. but we are talking forcing encroaching on 20k lbs of force..... I'm no material scientist...

 

Delrin has a tensile strength of around 11ksi, UHMW is around 5ksi, and aluminum 6061-T6 is around 45ksi. Delrin is about 25% as strong as the aluminum version, and I suspect would put the collar much closer to the range to break under normal use, but it is hard to know.
If anyone is serious about testing a delrin collar or full delrin version, send me some money and I will make and test one with a delrin collar, and I will even make and test one is that is all delrin.

 

I would think that as long as the rope doesnt exert enough force on the collar cutting/sheer force (it'll slip on the aluminum it wont cause any issues an inner ring would be the best I imagine as the inner only sees the shackle, and can be clocked to not damage the shackle... just a thought...

 

The tensile strength doesn't really matter since it will be in compression. It's still probably 25% of aluminum, but I wouldn't really be concerned about a compression failure. I would worry about it deforming around the central hole, but you could potentially press in a thick wall aluminum sleeve for the ID. But a 5"x1ft rod of Delrin is about 4x the cost of aluminum so it's gonna be left for theory for me.

 

I made a run in orange. If anyone is interested, PM me, or check the link in my signature.

 

I was just about to post this. It's interesting. I would like to see a more scientific test done. I think there are some definite advantages to the rings. Lightweight, eventual lower price than a block, higher probability of a Made in the USA product, less likely to damage the line if it slackens and slips out of the sheave, and captivity of the ring inside the actual rigging. I think the video could be used to make the case for both. I'm not sure if I have faith in chinamart blocks and the Masterpull USA made ones are $300-$400 plus shackle.

I just watched the second video. It convinced me that the rings are the way to go.

 

So. Put some pretty hard use into my 7p snatch rings in the last couple weeks. I’ve found they get really warm. I’m not real happy about that.

 

What temperature is “warm?” Dyneema SK75 is permanently degraded and looses strength at extended exposure to 176*F.

 

From here https://www.reference.com/world-view/temperature-human-skin-burn-82a1af6b1322b289

At a temp of 131*F third degree burns occur. At 162*F human skin burns immediately. If you can still touch the ring, it is less than 118*. There is no practical way that damage is being done via heat to the winch line.