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PostPosted: Tue Feb 02, 2010 11:35 am 
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Hi all

is it safe / ok to extend a draw/biner directly onto another draw
in other words metal on metal.
see pic below

thanks
vernon


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PostPosted: Tue Feb 02, 2010 11:53 am 
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The answer is no.
It is not ok to clip a 'biner onto another 'biner.

The clipping as show in the pic is unsafe.

Rather clip the red sling directly into the golden DB quick-draw.
The extra 'biner can be left dangling on the red sling, or can be removed.

It also looks like the red sling has rubber biner-keepers on both ends.
Personally I find that impractical and troublesome when climbing.
On that note:
Never put rubber 'biner-keepers on both ends of a quick-draw. Place it only on the rope end.
Leave the rock end 'biner free. This is a safety issue which I need to show you in order to explain.


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PostPosted: Tue Feb 02, 2010 12:05 pm 
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thanks Hann


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PostPosted: Tue Feb 02, 2010 12:28 pm 
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It's not unsafe, it's just not best practice. You're adding more (unnecessary) links to you safety system, which I guess makes it slightly less safe, since each link carries a potential risk to fail. Then again, each piece is rated to 22kN (or more) so strength should not be the issue.

Basically, if you can follow Hann's advice, do it but, if you're way run-out on difficult ground with your strength waining and you manage to slot a piece, I wouldn't waste any extra energy trying to bugger around with the sling.

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PostPosted: Tue Feb 02, 2010 12:38 pm 
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Mark,

I beg to differ.

Carabiners are designed to take a specific load, in a spesific way.

Clipping a biner on a biner as shown causes a rotation of 90° (see photo) and places forces on both biners which they are not designed to take.

Also the reason that, when necessary, a mallion is used next to your belay loop and not a biner. This also causes 3 way loading on the biner, but that is another discussion.
When clipping onto a "D" or "Delta" mallion the loading on the biners should remain as they are designed for.


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PostPosted: Tue Feb 02, 2010 1:48 pm 
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Like I said it's not best practice, but if I have the choice between making the clip or fiddling with the sling to clip it correctly I know which option I'd take.

Those two biners look like they're being loaded correctly to me?

Hann wrote:
Clipping a biner on a biner as shown causes a rotation of 90° (see photo) and places forces on both biners which they are not designed to take.

Please explain further...

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PostPosted: Tue Feb 02, 2010 2:17 pm 
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I have been told that this is never to be done as it is possible to load the gate which can then open if loaded, similar to back clipping on sport. Imangine the ropedrag pulling the red sling upward. Hanns referance to the rubber biner keepers that are considered dangerous was due to an accident where the climber had effectively had only the rubber band holding him and not the sling and then fell on it. There was a video of it on this site about how easily it happens.

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PostPosted: Tue Feb 02, 2010 2:27 pm 
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wow! that's one serious good looking climb


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PostPosted: Tue Feb 02, 2010 2:35 pm 
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Agree with shorti! That climb looks like an awesome ride :bom:

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PostPosted: Tue Feb 02, 2010 2:42 pm 
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The 90° does not refer to cross loading.

Take 2 biners, clip them together and pull in opposite directions.
The gate on the one biner then faces 90° to the gate of the other biner.
1) Biners are not designed to take loading in such a format.
- Yes it is along the spine, but the shape and symmetry of the biners is the issue.
2) One of the gates will probably face the rock, which can then be pushed open reducing the biners strength to "open gate" rating as marked on all biners.

The rubber band:
The accident Wayne refers is true, but what I was referring to is the following.
- Take a normal quick-draw, with both ends rubbered.
- Then clip a bolt and climb past.
Usually the 'draw lifts with the rope. The biner clipped to the rock then either opens against the hanger's nut as the angle changes, or the spine gets angled between the nut and the hanger's spine/hole that it may break on loading.

We can debate this point at length, but the idea is to climb as safely as possible.
Neither biner-to-biner clipping nor overuse of biner-keepers fits in that category.

But yes. If I was pumped and about to take a ground fall unless I clipped biner to biner, I too would make an exception.
I would then rest and, before climbing on, make the necessary changes as to avoid taking a lead fall on a biner clipped onto a biner.


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PostPosted: Tue Feb 02, 2010 5:15 pm 
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Another reason not to do it is the lower biner notches or nicks the upper one.
Have a look at your quickdraws, the upper biner is normally a bit damaged where it loads onto the hanger. This can cause undue wear on your rope if it runs over these sharp bits.
I guess the hanger is alot sharper then a biner but it would still cause some damage, especially if fallen on. :afro:

I would guess the pic is Angel Falls?


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PostPosted: Tue Feb 02, 2010 8:30 pm 
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Real Name: Derek Marshall
Steel on steel clipping extends the runner by an extra 80mm. Which can make a diffrence to rope drag over a whole route. I choose to take my chances with the cons of steel on steel clipping, while reducing rope drag.


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PostPosted: Tue Feb 02, 2010 9:10 pm 
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You are so brave Marshall.


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PostPosted: Wed Feb 03, 2010 6:41 am 
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Thank you, you are so nice.

"The gate on the one biner then faces 90° to the gate of the other biner.
1) Biners are not designed to take loading in such a format.
- Yes it is along the spine, but the shape and symmetry of the biners is the issue."

Hann, I still not don't get this. Can you try again.


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PostPosted: Wed Feb 03, 2010 10:20 am 
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Have to agree with Hann on this one, metal on metal is never a good idea. The biners can easily twist and cross load or load the gates.

Metal on metal is a really bad idea in this case because the biners are DMM revolvers... the ones with the little built in pulley, which I am pretty sure is not meant to have a biner on it. If he came off something "interesting" might happen to the little pulley :shock:

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PostPosted: Wed Feb 03, 2010 11:45 am 
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Biner on Biner is not best practice because:

Notwithstanding the comments above,
in a clinical environment, where everything lines up, there should be nothing wrong with it. However, in reality, there is often twisting in a system, both on sudden uptake of load, and during load.
Biners are strong in 2 dimensions, but are weak if made to twist or bend.
Furthermore, twisting has a funny way of making biners 'climb around eachother' and unclip from eachother! Hard to replicate at home, but it really does happen. (Has happened once to me)

In industrial applications, where there must be a hard metal-on-metal link, one of the two biners/links is made as small as possible, and the other large as possible to prevent this.

Best

ant


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PostPosted: Wed Feb 03, 2010 5:14 pm 
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Thanks Ant, but still not clear to me how twisting happens on an actual route. I can twist clips apart with/in my hands, but can't visualize this happening in a real situation.


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PostPosted: Wed Feb 03, 2010 7:51 pm 
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Ropes get twisted, especially when tradding, the twist catches the draw as the rope moves through it. The draw moves upward and twists against the other one.

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PostPosted: Thu Feb 04, 2010 8:41 am 
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The biggiest reason why I don't make this a habit is becuase of the damage that is caused to the rope end biner as mentioned by Rastaman.

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PostPosted: Thu Feb 04, 2010 9:40 am 
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Hann mentioned in an earlier post about only having rubberised biner-keepers on one side of a quickdraw; something I've heard numerous times. Funny thing is, when I bought my Singing Rock quickdraws about 4 or 5 years ago, they came equipped with them on both sides. I've taken a few whippers since I've owned them, with no (noticable) problems. So, either Singing Rock did something rather questionable in terms of their design, or maybe it's not as dangerous as we tend to think?


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PostPosted: Thu Feb 04, 2010 10:03 am 
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Ummm,

It is indeed as dangerous as advertised.

Check out: http://lifeinthevertical.blogspot.com/2009/04/quickdraw-this-could-save-your-live.html. The sewn-in side of a quickdraw is not in danger of this happening - if you do not have a keeper on the other end you notice any odd snarls in the draw; with one on you might not.

While the problem is not as bad with a formed rubber keeper - the problem is still there.

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PostPosted: Thu Feb 04, 2010 10:44 am 
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mjs wrote:
Hann mentioned in an earlier post about only having rubberised biner-keepers on one side of a quickdraw; something I've heard numerous times. Funny thing is, when I bought my Singing Rock quickdraws about 4 or 5 years ago, they came equipped with them on both sides. I've taken a few whippers since I've owned them, with no (noticable) problems. So, either Singing Rock did something rather questionable in terms of their design, or maybe it's not as dangerous as we tend to think?


Not wrote:
It is indeed as dangerous as advertised.

Check out: http://lifeinthevertical.blogspot.com/2009/04/quickdraw-this-could-save-your-live.html. The sewn-in side of a quickdraw is not in danger of this happening - if you do not have a keeper on the other end you notice any odd snarls in the draw; with one on you might not.


@mjs: it is dangerous for two separate reasons. Reason one) As in the link provided by Not. Reason two) What Hann means is that it is possible for the quickdraw (if equipped with a 'biner keeper on the rock/hanger side) to ride up the rope as you move past the bolt and un hook itself from the hanger...

For a scary demo: Find yourself a bolt close to the ground a clip a quickdraw (with 'biner keeper on the rock side) to it. Move the quick draw upwards so that the hanger runs across the gate of the 'biner. It should unclip itself

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PostPosted: Thu Feb 04, 2010 11:03 am 
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Luckily, the webbing used on my quickdraws is fairly rigid (hence not allowing the draw to bend sufficiently to get tangled and unclip itself) and both ends are sewn quite tightly, with the rubberised keepers apparently just making sure that the draw doesn't turn upside down; something which I find quite annoying in a couple of my newer draws. Nothing worse than balancing precariously (yes, I still manage to balance precariously on around a grade 18 or 19 sport route), clipping into the bolt, then having to try and try fiddle the lower draw around so that I can actually clip the rope...... Actually, I lied - worse would be falling before managing to get said draw the right way round... :lol:

I have, however, experienced first hand what was shown and described above with an extended quickdraw (which was made up of two draws attached to a long sling), at a belay point 15 meters off the deck; where the entanglement and subsequent "biner only attached to the rubber" bit did actually occur in my pack..... needless to say I have learnt my lesson there!


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