Pretty sure hitching wire is ill-advised.

Anyone have any stats on strength reduction on plastic-coated wire?

Re: Slinging Camalot Jr.s
Author: Chris Harmston
Email: chrish@bdel.com
Date: 1995/06/06
Forums: rec.climbing

On 4 Jun 1995, Neal Weiss wrote:
> I've given qll my Camalot Jr's (4) and several old unslung Aliens an after
> market sling job at Ragged Mountain in New Hampshire. Don't know how BD
> is slinging the Jr's, but Ragged Mountain did a great, straightforward
> job; 4" or 6" nylon slings (choice of color)for about $3 each. Spectra
> slightly more. All professionally and competantly bar tacked.
> Neal Weiss
> weiss@escape.com

Slinging Camalot Jr's requires that the webbing be doubled where it
contacts the plastic thumb bar. The inner webbing is not structural but
protects the outer from the cable. A simple loop sling is not adequate
and will fail at loads well below the 12 kN rating.

Chris Harmston (chrish@bdel.com)
Quality Assurance Manager/Materials Engineer
Black Diamond Equipment Ltd.
2084 East 3900 South, SLC, UT 84124 phone: 801-278-5552



--------------------------------------------------------------------------------


Re: Reslinging cams
Author: Chris Harmston
Email: chrish@bdel.com
Date: 1995/11/13
Forums: rec.climbing

On 12 Nov 1995, Steven W. Tregay wrote:
> For old style camalots you can cut about 1/4" off each side of the black plasic
> and then fit a camalot Jr thumb piece and then sling. This only works on 1 and
> 2's. This was in a quick clip in climbing some time this past spring.

This may have been in quick clips, but this is not recommended by Black
Diamond in any way. The following is a letter I sent to Climbing magazine
following another letter to them regarding slinging Camalots.

April 21 1995

In reference to the Quick Clips (#151) by John MacDonald regarding the
retrofitting of double stem Camalots with Camalot Jr. thumb loops and
slings I am writing to state that this practice is not endorsed by Black
Diamond Equipment. We feel that this situation described and depicted in
Quick Clips is potentially dangerous.

1) Cutting the Nylatron Thumb Bar down to make room for the Jr. Thumb
Loop may create two potential problems. First, if in cutting the
Nylatron Thumb Bar you are to damage the cable in any way, this could
affect the strength of the Cam. Second, the Thumb Bar and trigger
assembly are designed to each other. Cutting the Thumb Bar short may
cause the trigger to bottom out on the Thumb Bar and not enable full
retraction of the cams.

2) Sewing slings on the Jr. Thumb Loop requires overlapped webbing. A
single layer of webbing as depicted in the diagram is insufficient. When
testing these situations we have found that the Thumb Loop will break
near 1000 lbs. After that the webbing is in contact with the cable. For
the single webbing situation the webbing is cut by the cable at loads
between 1500 and 2000 lbs. These forces are relatively easy to achieve
in normal climbing situations. Therefore, it will be possible to see
sling failure and possible injury from this situation. Black Diamond now
sews its Camalot Jr's. with runners that have a double layer of webbing
around the cable and Thumb Bar. The Thumb Bar still breaks at about 1000
lbs, but the runners do not break until near 3000 lbs. In fact, about
half of the batch test samples fail at the cable and the other half fails
at the runner. We do not recommend that you put runners on old style
double stem Camalots. If you need a runner on you Camalot Jr. then send
them to Black Diamond for a retrofit.

3) A doubled or girth hitched sling on either Camalot is also not
recommended by Black Diamond. The reason for this is that the runner
still has no protection from the cable. For the Camalot Jr. sling the
inner webbing is not structural, it is there to protect the outer webbing
which is the structural component. The sling is sewn in such a manner to
prevent the structural outside webbing from ever contacting the cable.
The inner webbing is sewn to the outer and this keeps them both in place
(i.e., the inner against the cable and the outer away from it).

Chris Harmston (chrish@bdel.com)
Quality Assurance Manager
Materials Engineer BS, ME
Black Diamond Equipment Ltd.
2084 East 3900 South, SLC, UT 84124
phone: 801-278-5552


Re: New slings for Camalots?
Author: Chris Harmston
Email: chrish@bdel.com
Date: 1998/01/08
Forums: rec.climbing

See below for some more information you all may find enlightening.

On 7 Jan 1998, Stefan Axelsson wrote:
> In article <01bd1ae5$2f449a60$7d260ea7@cweaver>,
> Chris Weaver wrote:
>
> >While I admit that I didn't know BD's official opinion was this, it doesn't
> >address the point I was making. The point is that the tied sling is fine -
> >it's strong ENOUGH. The fact that it fails below the 12 kN rating proves
> >little. Your other gear will break long before the sling does.

I don't think tied slings are fine in all situations. They break well
below that of sewn slings, are prone to untying themselves, and I know of
accidents involving them (untying and cutting on Camalot cables). In
nearly every situation you will not generate enough force to cut or break
webbing or hardware. If you have a high fall factor with nearly static
belay (i.e. aid soloing is the most dangerous form of climbing in my
opinion because the forces are higher--if you use static belays) you
dramatically increase the possibility of failure.

> No they're not. The reason that you haven't heard about the cam
> cutting webbing in the way that you describe I would attribute to:
> 1) Not that many tie webbing like you describe,
> 2) Not that many take high factor falls.

I agree with these comments. The number one issue is that most people do
not hear the details of accidents. I have investigated quite a few gear
failure incidents. Gear does break during normal situations encountered
in climbing.

> Now, 12kN isn't that much to begin with in the first place, if you
> double that, not exactly true due to friction but we have to start
> somewhere, you land at about a factor one fall. Catch that with one of
> the more static belay devices on the market and the little red warning
> lights are sure to go off.

> >Black Diamond uses the 3-Sigma system to determine necessary breaking
> >strengths, and these strengths are far, far above what is necessary
> >in the field.

Absolutely incorrect. Just because we give a rating does not in any way
mean the product will not break. It is possible to break every piece of
equipment we make if the conditions are just right. Our rating system is
just that, a rating of where the gear fails when new and when tested in
the lab. We make products that will not hold falls. Climbers use these
to protect themselves routinely. So why do we do this? If we were to use
the strict engineering safaty factor rating and guarantee that you would
never break gear in any situation encountered in climbing then you would
not be climbing. Camalot Jr's would be for 8 inch cracks and would weigh
10 pounds. There would not be any Stoppers or Steel nuts. Carabiners
would be three times heavier and all would have autolocking sleeves.
And, you would all retire your ropes and gear after even the smallest
fall. So why do we sell gear we know has the potential to fail? Because
we are climbers and we recognize the need for the protection we sell.
Technique is what protects you foremost, not the gear. Placing protection
often to reduce the fall factor, equalizing small nuts, using low impact
ropes (carefull with these since they may stretch you into a ledge), etc.

> Whether BD use 3-sigma or slaughter a chicken at full moon to decide
> *breaking* strengths of their gear is of course totally irrelevant to
> the discussion of whether the chosen strength is sufficient or not.

The chosen strength of "12 kN" is not enough. You can generate more force
than this. It does not happen very often though. 12 kN is the force
chosen by the UIAA and CEN to be the limit of force in the rope during the
first drop of a factor 1.8 fall (and just happens to be the 3 sigma
strength of our Cam Jr's). This is not the force felt by the edge
they drop the weight over. REI has conducted drop tests and measured the
forces at the climber, belayer, and protection. They found that the force
on the protection is about 2/3 greater than that in the rope. This means
that the protection can see forces approaching 20 kN. Use an old fat rope
and you could generate even more force than this.

> As anyone with a background in mech. eng. can tell you, if you started
> rating other gear used in safety critical applications with the
> max. expected breaking load, instead of the more common 3 times safety
> margin to the yield stress of the material, you'd be out of a job. So,
> no, they are *not* "far, far above what is necessary in the field."
> Quite the opposite actually. Ask anyone involved in rescue work.

Correct. Climbing gear is not engineered to never fail. It is not
possible given the currently available materials and designs and costs.
Technique is what protects you foremost. Blind faith in anything is not
sound advice.

> That BD does not unnecessarily and purposely wish to introduce a weak
> point in their design by recommending that you tie a sling the way you
> have advocated in my mind reflects very favorably on them. Especially
> since the design impact is neglible in terms of cost, weight etc.
>

Single loops cut on the wire of the Jr's. These loads range from 1500 to
2500 lbs. With the doubled loop the cable breaks at loads over 3000 lbs
(rating is 12 kN = 2698 lbf.). We feel that the use of single
loops is not sound advice. They are still strong enough for the vast
majority of situations you could encounter. End BD recommendations.

The following recommendation is my personal one and is not to be taken as
recommendations by Black Diamond. I use single loops. I recognize the
limitations of doing this. I know that these can fail at much lower
loads. I never use these as the only piece of pro when there is the
potential for a high fall factor. I use double loops so that the webbing
can be extended. I also cover the wire with a 1/4" thick layer of
fiberglass tape and athletic tape to help protect the web from the cable.
Using tied slings is fine for many situations. I don't use them if I have
a choice.

Irrelevant FYI.
I have been climbing since 1981. I have onsighted 12- trad and 12+ sport.
I lead WI6 and have put up about 2 dozen first ascents on rock and ice. I
have no wall experience other than long free routes done in a day. Not
that this is pertinent to the discussion, but I am a climber. Safety of
gear is my hobby. Testing climbing gear is my job. I have BS degrees in
Physics and Materials Engineering. I have a masters degree in Materials
Engineering and quit my PhD program with 18 months to go so that I could
work for BD. I have been with BD for 5 years.

what would work great for me would be a doubled sling that is 8 inches doubled and 16 inches extended!!

edit: it was none other than j_ung

http://img90.exs.cx/img90/2181/Rackola.jpg

Slinging Camalot Jr's requires that the webbing be doubled where it
contacts the plastic thumb bar. The inner webbing is not structural but
protects the outer from the cable. A simple loop sling is not adequate
and will fail at loads well below the 12 kN rating.

2) Sewing slings on the Jr. Thumb Loop requires overlapped webbing. A
single layer of webbing as depicted in the diagram is insufficient. When
testing these situations we have found that the Thumb Loop will break
near 1000 lbs. After that the webbing is in contact with the cable. For
the single webbing situation the webbing is cut by the cable at loads
between 1500 and 2000 lbs. These forces are relatively easy to achieve
in normal climbing situations. Therefore, it will be possible to see
sling failure and possible injury from this situation. Black Diamond now
sews its Camalot Jr's. with runners that have a double layer of webbing
around the cable and Thumb Bar. The Thumb Bar still breaks at about 1000
lbs, but the runners do not break until near 3000 lbs.In fact, about
half of the batch test samples fail at the cable and the other half fails
at the runner. We do not recommend that you put runners on old style
double stem Camalots. If you need a runner on you Camalot Jr. then send
them to Black Diamond for a retrofit.

3) A doubled or girth hitched sling on either Camalot is also not
recommended by Black Diamond. The reason for this is that the runner
still has no protection from the cable. For the Camalot Jr. sling the
inner webbing is not structural, it is there to protect the outer webbing
which is the structural component. The sling is sewn in such a manner to
prevent the structural outside webbing from ever contacting the cable.
The inner webbing is sewn to the outer and this keeps them both in place
(i.e., the inner against the cable and the outer away from it).

Single loops cut on the wire of the Jr's. These loads range from 1500 to
2500 lbs. With the doubled loop the cable breaks at loads over 3000 lbs
(rating is 12 kN = 2698 lbf.). We feel that the use of single
loops is not sound advice. They are still strong enough for the vast
majority of situations you could encounter. End BD recommendations.

From that email I take it you need a 1000 lb force to break the protective cover of the stem followed by a 1500-2500 lb force.

Post the details...sounds like BS.

I don't care for the doubled over sling that BD puts on C4's. I thought it was bulky and stiff. I guess this sheds light on why they are doing it.

I like that the thumb loop is rigid, but I had wondered how structural it was. The alien thumb loop had struck me as a stronger design (however, the plastic coating has cracked on some of my older ones).

Breaking at only 1000 lbs strikes me as pretty lame. I wonder if they were really breaking at that low of a rating, or if they were really breaking at a higher value, but BD is publishing a lower figure of 1000 lbs because of liability concerns.

If it really is only 1000 lbs, I would expect reports of "broken thumb loop" to start showing up on rc.com.

I'm more likely to clip short cam slings directly when I'm climbing a straight-up corner or crack, and/or I need protection right now before I fall off or lose momentum. In those cases, a doubled sling is more fumbly and a tripled one would be worse. On a wandering face pitch, alpine or moderate climbing, on the other hand, I'm almost sure to use draws or even long runners; a doubled or tripled sling would be helpful and let me carry less gear.

What would you guys think of putting a 18" x 12mm Dyneema sling on the cams? You'd thread the sling like a trad draw (tripled) so it would carry like a 6" sling but would easily extend to an 18" runner. No more doubled up 'biners, no more QD's on trad pitches.
Mal

I'd prefer if your doubled slings were a bit longer.

I find tripled slings too much of a fustercluck. And, since I typically carry and use (even on the most wandering and devious backcountry pitches) only ~10 single-length and two double-length runners (for a rack of approx. 14-20 cams and a full set of nuts) the presence of tripled slings on every cam would likely increase my total rack weight, rather than reduce it... bearing in mind that I would still need to have full-length runners for any stopper or tri-cam placements I'm likely to make.

But that's a very interesting idea, and I wouldn't reject it out of hand. Always willing to at least try out new ideas.

Old dog, comfoozed but still gamely looking for new trix,

Brutus

Don't have em, wish I did. Alan Jolley and Todd Vogel did the tests about 3 years ago. A mutual friend told me about it, and a IFMGA guide confirmed the findings when I asked them about it. The guide I asked doesn't post online, so I'm not gonna involve them by using their name.

What was found was that when your low on biners (well into a pitch, with a lower fall factor) and you double a sling through a wire (1st choice) or girth hitch the sling (2nd choice) you'll be ok.

The slings held more than 10kn. It might have been 9kn sometimes...but it was enough to have confidence in.

Small wires were more of an issue, but the wire would still break before the sling cut (according to THEIR tests). The girth hitch failed before a sling doubled through and clipped on both ends...your first choice.

I don't remember if they tested both specta and nylon, or only 1, and which it was; I don't know if it was slow pull testing or drop tests...but I know what their conclusions were.

So, that said, I do it whenever a biner would be loaded over an edge, or I'm too low biners (hasn't happened yet).

So, thats all I know about it. Hope it's worth something to ya'.

Jim

What would you guys think of putting a 18" x 12mm Dyneema sling on the cams? You'd thread the sling like a trad draw (tripled) so it would carry like a 6" sling but would easily extend to an 18" runner. No more doubled up 'biners, no more QD's on trad pitches.
Mal

I'd prefer if your doubled slings were a bit longer.

I find tripled slings too much of a fustercluck. And, since I typically carry and use (even on the most wandering and devious backcountry pitches) only ~10 single-length and two double-length runners (for a rack of approx. 14-20 cams and a full set of nuts) the presence of tripled slings on every cam would likely increase my total rack weight, rather than reduce it... bearing in mind that I would still need to have full-length runners for any stopper or tri-cam placements I'm likely to make.

I've seen the results of the pull tests that Alan and Todd did. A few days ago Alan showed me the two 10kN stoppers he used in his pull tests where the wire loops on the stoppers were both broken by the same spectra sling. In one pull test the sling was doubled thru the stopper loop and the other test the same sling was girth hitched thru the stopper loop. In both cases the wire broke at the point where the sling contacted the wire and he said that both stoppers broke right around their 10kN rating. There was absolutely no damage to the sling at the point of it's contact with the stopper wire. So, yes, you may get some strength loss when putting a sling on bare wire but the sling is so much stronger than the wire that the wire will break long before the sling is even damaged.


Tim

PS (edit): Their pull tests were a slow pull rather than drop. Alan told me what the pull speed was but I don't remember it off hand.

I climbed a backcountry route with a guy who used this technique. He had a number of half-shoulder length (12") slings each with a carabiner rubber-banded into position. He hung these off of a common carabiner on his rack, but I found this hard to manage so I clipped them to my harness like draws and let the free ends waft in the wind. It required a slightly different set of motions when clipping, but no big deal. And I have to admit that it saved a bunch of carabiners. I kind of liked the idea.