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 Post subject: D Shackles for bailing
PostPosted: Mon Jan 07, 2013 10:58 am 
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I spotted 3x D shackles that were used for bailing in Montagu over December.

D shackles are more dangerous than they're worth (when used for bailing), rather use maillons (quick links) or leaver biners!! A reasonable maillon will cost you R15 from a hardware store.

:idea: Remember: Do not to trust a single bolt when lowering/bailing - always back up.


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PostPosted: Mon Jan 07, 2013 11:05 am 
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Can you elaborate on why D's are more dangerous then Mailons. Is it that they may open more easily?


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PostPosted: Mon Jan 07, 2013 11:42 am 
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Yes, the pin working loose is the problem.

e.g.
- If weight is taken off the rope halfway down whilst lowering/abseiling, the shackle is unloaded and loaded again (basically movement that can cause the pin to loosen or the shackle to swivel 180' which takes us to the last point).
- The pin works loose because it is not tightened properly (no pliers available)
- If the shackle turns 180' and rope slips over it in the correct direction the pin can be loosened - see crude pic below.

It is unlikely that a D shackle will work loose, but the chance is there and it's just not worth the R10 saving + hospital time/body retrieval.
Use a biner or a maillon :thumleft:


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PostPosted: Fri Jan 24, 2014 12:05 pm 
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Well Justin, can you then please ask the Agrimark in Montagu to make sure they check their stock of mailons? One of those really old ones may be mine from that pipe bitch! :P (jk, I never bail, I take a sleeping bag up :P)

PS: Back in SA again, gotta regroup, refresh and weekend-trip it up there soon! I miss B&B...

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PostPosted: Fri Jan 24, 2014 3:44 pm 
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Welcome back!
The mailons are from the 'Build It' in Montagu... there is a great new (very easy) multi pitch going up (Cogmans Buttress which you are going to enjoy.

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PostPosted: Fri Jan 24, 2014 5:21 pm 
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Who in their right mind would bail off a D shackle? :shock:


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PostPosted: Mon Jan 27, 2014 12:31 pm 
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Quite! I'm surprised you can even get one through a hanger with a quickdraw in place, The mind boggles at the faff involved getting it in!


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PostPosted: Mon Jan 27, 2014 2:44 pm 
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I don't know how happy I would be recommending hardware store Maillons over D Shackles- that is sort of like recommending Nylon ski rope over shoe laces for rappelling off. If something is unrated, its unknown

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PostPosted: Mon Jan 27, 2014 3:33 pm 
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Warren is 100% correct.

However I personally trust (these particular) hardware store maillons as they're about 10mm thick + you should be lowering off x2 of them. I've hung on enough unrated and thinner chain to trust them (said maillons).
Maillons are still safer than D shackles as they don't have a pin.

I did ask someone a while back if he could test a few of these maillons - unfortunately it never happened. Is there anyone out there who would be able to stress test a few?

For the record I would not lower off shoe laces :)

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PostPosted: Mon Jan 27, 2014 3:45 pm 
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Maillons are not the name of the item, it is a specific brand name. A Maillon rapide is French made, and the rapide of choice in skydiving equipment. I would, and did, trust 'maillon' with my life. However you get cheap knock-offs that Im not sure about. My point is, it may look like a maillon, but if it doesn't say maillon, its not. If it does..trust it. :thumright

Quote from UK Airsports -

"Maillon Rapide are manufactured in France by Peguet and are the best quality steel connectors available! Beware of cheap imitations..."
http://www.peguet.fr/


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PostPosted: Mon Jan 27, 2014 8:10 pm 
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I would love to hear about a stress test on a maillon even a cheap hardware one. I'm guessing it will probably take well in excess of a ton without failing which is easy more than belaying off of it.


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PostPosted: Mon Jan 27, 2014 9:26 pm 
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Give us some, the next time we're drop testing gear with ~200kgs we'll use them as the critical point...

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PostPosted: Tue Jan 28, 2014 7:25 am 
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Nic, when are you testing again? I'll get a few of them to you.

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PostPosted: Tue Jan 28, 2014 8:05 am 
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Cheap knock offs from a hardware store is quite a gamble. Those are/were mostly designed for setting up wash lines etc. It has not got a rating stamped on it and in most cases is made from a local manufacturer or from China. It is merely a steel rod bent in that shape with a screw 'gate' to keep it closed.

You can at most climbing stores buy the proper equipment:

Things to consider before using cheap knock off ''Maillon'' type connectors:

The following info is based on the Maillon Rapide (Demi Rond)
EN 362 (meaning it is a connector, karabiners share the same number)
25kn load along the ''spine'' , work on a safety factor of 10% = 2,5kn
10kn cross loaded, work on safety factor of 10% = 1kn

Even if a Maillon cost nearly the same as a karabiner I would still spend the bucks to buy something safe. It is not worth it to use incorrect equipment as explained by some above.

I guess another option could be a Four Part Shackle, this is still the shap of a D or a Bow Shackle. It then has a pin that goes through and is fasted by a Nut. It has a hole to put an R clip through to prevent the Nut from coming off. The pin in a sense can move and ''run'' like a pulley but it should not under normal circumstances unscrew from the pin. There are many options but the cheapest screw gate Karabiner is roughly R60 - R80, as apposed to a Hospital bill or an expensive chopper ride.

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PostPosted: Tue Jan 28, 2014 8:06 am 
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I was meant to add that I could later this week to some Pull tests on various knock offs and will post some pics

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PostPosted: Tue Jan 28, 2014 8:35 am 
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Trevor wrote:
I guess another option could be a Four Part Shackle, this is still the shap of a D or a Bow Shackle. It then has a pin that goes through and is fasted by a Nut. It has a hole to put an R clip through to prevent the Nut from coming off.

Are you referring to something like the one in the photo I inserted below?

Trevor, thanks for the offer, I'll get a few of the hardware maillons to you (I'll message you for details).

Since you appear to be in the know 8)
Chain links: What measures can one take to ensure that one is buying quality chain (for use as top anchors)?


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File comment: D shackle with pin
d_shackle_nut_pin.jpg
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PostPosted: Tue Jan 28, 2014 9:03 am 
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Justin wrote:
Nic, when are you testing again? I'll get a few of them to you.


24th of June

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PostPosted: Tue Jan 28, 2014 11:08 pm 
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I think a drop test will be interesting but what I think is really needed is equipment which allows you to slowly increase the weight until it fails, because we are talking about using this for lowering off / not to take a shock load / fall. E.g. a factory crane with a 500 kg weight and a maillon in the system and see if it pulls open for example. Then just from a logic perspective isnt "a rod with a screw gate" better than the spot welded chain I have seen as anchors?


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PostPosted: Tue Jan 28, 2014 11:27 pm 
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Yes, it will be best to test the equipment in a lab (like in the article linked below). I'm hoping that Trevor has this equipment!

Related article: Lab test of carabiners used at belay stations

Mark wrote:
Then just from a logic perspective isn't "a rod with a screw gate" better than the spot welded chain I have seen as anchors?

I think it would depend on a few factors such as type of metal, type of weld, thickness of rod/chain link...?

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PostPosted: Wed Jan 29, 2014 8:09 am 
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Not to put a damper on the lab test as it is good proof but there are some basic design considerations that should put your mind at ease;

When talking about steel the strength of an industrial snap gate would relate directly to the diameter of the bar & the hook & loop closure i.e. it is the cross section that counts, but with an industrial shackle this would boil down the the cross section of a single thread where the nut goes. The additional factor we should all have learnt from DMM is that normally the load is carried by the spine of the carabiner or maillon or whatever (D shackles do not apply) So what we are saying is that until the force is big enough to start opening out the steel d shackle the forces are shared between the "spine" of the shackle & the thread - they will find the weakest one of the two. So for this argument it depends on a diameter 8mm cross section or the cross section of one thread. STILL AWAKE? If you do the maths - first year engineering - but I don't have the time you should be able to carry more then the static weight of your average Capetonion climber (110 Kg or so...). Now unless the hardware shackle is made from chewing gum you should be able to abseil from it - especially with the gate screwed closed.

I have my reservations about 6mm "maillons" or industrial shackles, I fully agree that the D shackles are a recipe for disaster & I believe that Chinese steel is suspect, so a test would be good (if not entirely representative)> of course it goes without saying that this is for getting off a sport climb & not for anything involving shock loads etc.

What we need is more people using their brains & less people taking unnecessary risks with life & limb just because they are cheap!

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PostPosted: Wed Jan 29, 2014 9:47 am 
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Justin wrote:
Welcome back!
The mailons are from the 'Build It' in Montagu... there is a great new (very easy) multi pitch going up (Cogmans Buttress which you are going to enjoy.


Probably last weekend in Feb or begin March. I'll give Cogmans a go, I have actually never climbed there. Now to regroup the climbing buddies and shake the american fried frenzy (refer "the static weight of your average Capetonion climber (110 Kg or so...)")

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PostPosted: Wed Jan 29, 2014 9:52 am 
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Mark wrote:
I think a drop test will be interesting but what I think is really needed is equipment which allows you to slowly increase the weight until it fails, because we are talking about using this for lowering off / not to take a shock load / fall. E.g. a factory crane with a 500 kg weight and a maillon in the system and see if it pulls open for example. Then just from a logic perspective isnt "a rod with a screw gate" better than the spot welded chain I have seen as anchors?


A static pull test (to which you refer) would give the strength limit of the "link" (what ever it is: D shackle, maillon etc) but that's not what we're interested in really. As Old Smelly says above, the "links" will be more than strong enough to take the weight of a climber gently getting on to them and abseiling.

What is more interesting is the worst case scenario event. Imagine you are finishing the route. Get to the chains. Clip in directly to the chains (as I have seen many, many people do), pull up a bit to sort out your feet/rope/harness/nut sack and slip, falling onto the "link" directly, possibly with a static sling (also common practice). What then? That kind of dynamic load is simulated quite well with a drop test. We can also simulate what happens when different parts of the "link" are on the hanger when it is loaded.

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PostPosted: Wed Jan 29, 2014 10:23 am 
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Oh and something else:

Climbing gear generally is designed to "automatically" orientate so that the load is placed along the strongest axis, hence the asymmetrical design of most carabiners. It is designed this way precisely because of the chance of unexpected dynamic loads. Industrial gear (particularly D-shackles) is not designed with unexpected dynamic loads in mind because (in most cases) it can be checked before it is loaded to make sure that it is orientated properly.

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PostPosted: Wed Jan 29, 2014 10:29 am 
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Yes Justin, that is similar to what I was thinking but i forgot to add that it is still not 100% safe alternative. Keeping in mind that the split/R pin is there merely to keep the nut from popping off in the event of it unscrewing itself. remember the pin in place will not act as a Nut and in turn wont stop the pin from coming out.

I will try chat to a buddy here in durbs and hopefully can get cracking with the testing on friday. I have quite an arrangement of 'Maillons', from hardwear stores to old parachute to old riser conenctors for paragliding. Also different diameters and sizes

Will keep all posted

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PostPosted: Wed Jan 29, 2014 10:34 am 
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First things first... calling us Capie's fat! :cheese: (although I see Funguye has just posted / arrived back! :)

Thanks Trevor - I did mail you.

I hear you: a carabiner (loaded on it's spine) is as strong as the gate - which (generally speaking) makes maillon's stronger.

I've seen some really crappy hardware out there (and none of it has broken - take for example the - the thin brown chain (see pic below) comes from the Steeple as was replaced with quick clips (thanks to CityROCK/Montagu Bolting Fund). WRT to the thin brown chain - a climber once got attacked by a dog when the dog broke a chain of the same diameter!!

Then you have 'Cold Shuts' which most people probably don't know about (which is a good thing). It literally is a a steel rod bent into shape - I don't know of any failing but (besides it being of weak design) there was concern about the rope running over the bottom bend and heating it up which means it would be more prone to bending open. You also get the Cold Shuts where there is a gap big enough to put your rope over the top and inside (meaning that you don't need to untie).

The Vector hanger with the 'worn' chain is from the top of Gospel Express (which Roger Nattrass replaced).

The shiny chain links are 10mm thick and from the hardware. I have been using them for top anchors - I'm hoping to get them tested in the lab too.
As mentioned the hardware store maillons I'm talking about are 10mm thick.

This reminds me the top anchor of 'Hey Come On' is a single marine/hardware biner (it's actually the top anchor for 3 different routes) - I will replace it as soon as I get some more hardware.


Attachments:
File comment: Climbing chains and top anchors
climbing_chains_top_anchors_climbing_01.jpg
climbing_chains_top_anchors_climbing_01.jpg [ 72 KiB | Viewed 433 times ]
File comment: Cold Shut rock climbing
cold_shut_climbing_hardware.jpg
cold_shut_climbing_hardware.jpg [ 52.73 KiB | Viewed 433 times ]
File comment: The way I am setting up top anchors at present
top_anchors_IMG_2427.jpg
top_anchors_IMG_2427.jpg [ 101.35 KiB | Viewed 433 times ]

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PostPosted: Wed Jan 29, 2014 2:02 pm 
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Good post Justin, (and well observed)

Top anchors are one area where we all need to be careful to install the very best. Using a hardware store "maillon" may be acceptable for escaping a route, but skimping on top anchors of a route is not the way to go. Justin has shown examples of good anchor installations where the rope does not pull the bolts towards each other & where one can clean easily.

Whether below the rock face or the equipment we use we need to do the best possible job. So if it is a bit more for 316 bolts or the correct chain or anchors then ask around for some assistance funding your climb rather then doing the rusty chains thing. The gear is available to do a good job so please do not do a bad one. Following that lets report all worn chains & bad anchors to all the climbing public.

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