Pro's and con's of Carabiners and screw hardware

[jwp]

Pro\'s and con\'s of Carabiners and screw hardware

Screw hardware seems to be less expensive than say a locking screw carabiner. I like the idea of having a multi action carabiner so that there is less chance of the gate opening by itself.

My current set up uses a screw delta where it hooks to the saddle so maybe just a screw gate is acceptable. I don't know. But along this line of thinking would a screw oval be an acceptable way to connect to a hitch pulley?

Please educate me about these items.

 

[SRTsteve860]

Re: Pro\'s and con\'s of Carabiners and screw hardware

The problem with screw gate carabiners and different screw links (delta, oval, shackle) is the type of threads that are machined onto the metal. The threads on an actual connecting link are much coarser and deeper than those on a carabiner, thus with more material in each thread, this allows the piece of hardware to sustain greater loads when compared to one of similar sized stock with smaller threads. The small threads of a screw gate carabiner can be rounded over much easier with the routine tightening and un-tightening of its use, and when the threads start to be compromised then the WLL of the piece is compromised.

A connecting link is designed to be tightened and "locked" with a pair of pliers, and it is capable of sustaining the resulting shear force that is placed on each thread. If you were to "lock" a screw gate carabiner in the same fashion, you would ruin its functionality in short order.

That is just a mechanical reason between the difference of a connecting link and a screw gate carabiner. In many sport climbing fields they are still used and are still safe, as long as the regular gear inspection takes place pre/post climb, whenever switching over to a new system, ect. The caveat is that they are not allowed in the professional rope access field, and since most rec climbers are also production climbers, they use the hardware they currently own, and to their benefit too, because auto lockers will snap shut when connected, where as a screw gate needs to be spun shut every time its connected.

as for your hitch-tending pulley, will the pulley be on its own separate carabiner than the rest of the climbing system? Or will there be one carabiner which has your hitch cordage and pulley together. If its on its own independent link you can get away with just a dog leash snap, as its not needed for life support, but if you are going for a more compact system with the hitch tending pulley together with you cordage for smoother slack tending, then i would suggest either an oval or HMS style auto locker carabiner.

Hope this helped a little,

-Steven

 

[jwp]

Re: Pro\'s and con\'s of Carabiners and screw hardware

Yes this information helps. Now I know why my delta link has a hex nut for closing the gate. It is designed to be tightened with plyers. If I remember correctly I was told to tighten the delta link finger tight and the back it off about 1/4 turn. Apparently this is bad technique.

The screw gate carabiners that I have appear to have a small steel ring that sort of binds the gate when it closes. I can see how the carabiners threads could be subject to wear.

 

[moss]

Re: Pro\'s and con\'s of Carabiners and screw hardware

Yep, New Tribe harnesses use the delta or pear screw links at the main attachment point. In over 8 years of facilitating climbers on NT harnesses I never tighten the links with a wrench. They are intended to be finger tightened for this use. The links are double threaded and require quite a few turns to open enough for any of the harness parts to disengage. Even then it's a bit of work to get the link off the harness with the link wide open. If the link opened enough to create a small gap it is quite strong enough to handle significant climber load, not like an alloy carabiner, it won't fail in those circumstances. Finger snug will not come undone when used on an NT harness. Check with the harness manufacturer, they will say the same.

If you are using a delta for heavy rigging purposes you must tighten with a wrench. That is a completely different use scenario.
-AJ

 

[moss]

Re: Pro\'s and con\'s of Carabiners and screw hardware

I agree that screw lock carabiners are a bad idea for tree climbing. They open too easily, too few turns and the carabiner's strength is significantly compromised with the gate open. For winter climbing screw gate biners really suck, too much dexterity required with frozen fingers. Find an autolocker you like and stick with it. Always verify the gate is locked when you use an autolocker, a sharp tap on the gate will do it. Nothing is foolproof, always take a look at your life support connections during your climbs to make sure everything is staying shipshape.
-AJ

 

[moss]

Re: Pro\'s and con\'s of Carabiners and screw hardware

I don't currently climb on an NT harness but when I did I would rarely open the screwlink. If fitted properly you should be able to slide into the waist belt without undoing the link. Even then I still finger tightened and never had one open over many climbs in very challenging situations with plenty of harness/tree contact.
-AJ

 

[Tom Dunlap]

Re: Pro\'s and con\'s of Carabiners and screw hardware

If you choose to tighten a screw link be VERY careful!

At most you don't need much more than finger tight. Take a look...you'll see 6 flats on the sleeve. Tighten by hand and then use a wrench, not pliers, to turn it NO MORE than 'one flat' or 1/6 of a rotation. That's all you need. Be sure to keep the wrench handy because it will be impossible to open otherwise.

I've used screwlinks for decades and never used a wrench to tighten them unless it was a permanent connection. In all these years the most I've ever found one open is about 2-3 flats. That is not even enough to be a danger.

I've only used marine or Maillon Rapide screwlinks. There are plenty of low quality screwlinks available...is your life worth it?

 

[JontreeHI]

Re: Pro\'s and con\'s of Carabiners and screw hardware

X3 on hand tightening the delta. Always seemed overkill to me to use a wrench. It takes 10 or 12 rotations to even clear the threads.
I'm very comfortable climbing on finger tight links.

 

[jwp]

Re: Pro\'s and con\'s of Carabiners and screw hardware

Thanks Tom, Moss, and JontreeHI. I now feel more comfortable with the screw delta link. I have a couple of screw gate carabiners and I have found them unscrewing a few times. I don't like using them but I do use them for some things.