Chockstone Forum

      Sponsored By
      ROCK
   HARDWARE

Chockstone Photography

Australian Landscape Prints

Chockstone Forum - Gear Lust / Lost & Found

Rave About Your Rack Please do not post retail SPAM.

Author

The big trad gear destructo challenge

kieranl

1-Nov-2010
9:03:46 PM

Great stuff, thanks guys.

another dave

1-Nov-2010
9:12:32 PM

On 1/11/2010 Lee C wrote:
>Just rated the placements, really cool! It seems that 90% of the time I
>should harden up! Nice work guys.

I second that


monkeyboy

1-Nov-2010
9:52:24 PM

On 1/11/2010 another dave wrote:
>On 1/11/2010 Lee C wrote:
>>Just rated the placements, really cool! It seems that 90% of the time
>I should harden up! Nice work guys.

Pretty much the same for me too - though I don't mind being a little cautious.

mikllaw

2-Nov-2010
12:01:15 PM

Obviously there are differences between test and real world placements:-
• We are testing smoothly and in line, some fall conditions such as a slight outwards angle of load, rope movement, and shock loading may change the results. (Shock loading shouldn’t change the strength of materials much, but may affect cams a lot if they have to rotate to take load).
• I think rope movement dislodging pieces might be significant.
• Placing gear from a comfy abseil where you can move around, fiddle with both hands, and look from different angles is different to rushed placements from uncomfortable, tenuous positions. So I’d expect this gear to be better placed, and better assessed than gear in the field.

Most gear was a lot stronger than we expected, but ~ 10% was weaker, hence I'd recommend placing backups or doubles if "failure is not an option".

Most gear was a lot stronger than we expected, so why does so much gear come out in falls? I suspect rope movement (particularly overattentive belayers putting too much tension in the rope before a fall), but it could really be the dynamic loading thing. More work needed here.

mikllaw

2-Nov-2010
12:03:02 PM

Superstu has addded a docuement of failure notes for each piece, the wires that broke were above their rated sterngth, while one of the spectra cords broke well below its expected strength due to minimal abrasion.
http://www.sanguma.org/destructo

Estey

2-Nov-2010
12:55:59 PM

Eye opening and reassuring.

I expected a lot more failure due to blowouts rather than gear breaking.

Thanks to those who donated gear and did the testing.

mikllaw

2-Nov-2010
2:34:25 PM

yup
double up


ajfclark

2-Nov-2010
6:39:17 PM

Thanks guys that was really cool.


ambyeok

3-Nov-2010
9:38:26 AM

Was good fun. Some of the before after photos dont match. Needed more photos of the original placement from different angles in order to make a meaningful analysis.


Superstu

3-Nov-2010
10:09:54 AM

ambyeok: Some of the nuts used were "double nuts", i.e. two nuts on the one wire. It was very confusing to sort through the photos until we looked at a couple of photos taken of the whole setup from back and zoomed in heaps to poor resolution - but was able to positively identify each piece from colour. In hindsight we probably should have used tags in the photos like an archeology dig.

Unless you can eyeball a placement up close in person from several angles its fairly hard to assess any placement with any certainty; this limitation was mentioned on the first page. We did keep tabs of how the four participants rated the pieces before the tests. Mikl will give the stats on that. We didn't always get it right, generally being overly pessimistic.

How to simulate a "real fall"? Filling a haul bag with rocks and sending it over the edge is probably a good start. You won't get breaking load but if you can rate the haul bag's fall first and then repeat it with same conditions then you will have a pass/fail for a given load.

A haul bag with rocks will behave a little differently to a human. Perhaps we borrow pmonk's blow up sex doll and fill it with water?

kieranl

3-Nov-2010
10:22:56 AM

On 3/11/2010 superstu wrote:
>A haul bag with rocks will behave a little differently to a human. Perhaps
>we borrow pmonk's blow up sex doll and fill it with water?
Looks like a recipe for an incontinent sex doll - unless you can get one that's rated to 20 kn.


ambyeok

3-Nov-2010
10:57:15 AM

On 3/11/2010 superstu wrote:
>ambyeok: Some of the nuts used were "double nuts", i.e. two nuts on the
>one wire....

Righto. I did wonder what double nuts meant. That all makes more sense now. Go ahead and scrub my comments from the site if you wanna. p.s. Great work on throwing together a functioning site so quickly.


IdratherbeclimbingM9

3-Nov-2010
11:50:29 AM

On 3/11/2010 superstu wrote:
>How to simulate a "real fall"? Filling a haul bag with rocks and sending
>it over the edge is probably a good start. You won't get breaking load
>but if you can rate the haul bag's fall first and then repeat it with same
>conditions then you will have a pass/fail for a given load.
>
>A haul bag with rocks will behave a little differently to a human. Perhaps
>we borrow pmonk's blow up sex doll and fill it with water?
>
I would expect a haulbag filled with rocks to blowout if it was to fall any serious distance.
~> Tie a log weighing 80kg to the test line instead? ~> This used to constitute belay practice in the old days!!

Re placements
>generally being overly pessimistic.
>
>1. Red tricam sling broke 8.3kN
>The rated strength of these new is 9kN. The placement was very flared, so that the
>sling was pinched between the rock and the lip of the curved cam shape, tearing
>started here (arrow at lower picture). I was surprised the piece stayed in.

I wasn't. Although the placement was not ideal, I am a fan of these items and have seen them stay put in a lot of unusual placements.
Shame about destroying the item, as I am on the lookout for another red one for myself!!

Given many falls are < 8 kn I regard that as a success breakage!

>15. Unknown nut pulled 0.3kN
>We all rated this highly and it just sloughed out of the fairly reasonable looking
>placement at virtually no load.

It was a horizontal placement. even though it was a narrowing pocket?
If this is the case, I think it says something about horizontal placements in general.

mikl reckons to back these up. I agree, but I note that these placements are also where I have found tricams to work quite well when other items won't!

Thanks to all involved for testing and posting up those results.

hargs

3-Nov-2010
12:27:31 PM

On 3/11/2010 IdratherbeclimbingM9 wrote:
>>15. Unknown nut pulled 0.3kN
>
>It was a horizontal placement. even though it was a narrowing pocket?
>If this is the case, I think it says something about horizontal placements
>in general.

This is one case where video would be much more instructive than a photograph. That placement looked and felt absolutely bomber when tested by hand in the direction of load (i.e, several good, solid sideways tugs.) The rock was so pathetic that under load the material holding the piece in place just gave way like it wasn't there. Same placement in more solid rock would have yielded a very different result.

crm114

3-Nov-2010
8:25:26 PM

Those pictures and ratings were really cool.

Somebody on non-CS forum suggested that a wiggle test might have lead to some of these pieces falling out. I reckon I agree. A foot-kick test might have done the same.

I guess the other thing is, you are asked to rate the protection (bomber etc) whereas the results are how much load they each took which does not directly answer the question of whether they were good pro. Not entirely sure how you could do, but assuming a participant wants to know whether they have a crap eye for gear placements or should just harden up, it would be worth coming up with an agreed rating for the piece (ie bomber etc) from those who set it and/or an aggregate result from the people particpating in rating them.

Separately, it would also be cool to see the ratings vs the failure load of each of those pieces that breaks just to see how they do (for those pieces that actually have the rating still onj them).

crm114

3-Nov-2010
8:29:38 PM

Sorry - some of this info is in the "failure notes" - wouild be cool if it flashed up when you submit each rating.

Philtown

4-Nov-2010
8:39:34 AM

I went to school at Lucas Heights (Barden Ridge now, since the locals didn't want to be associated with their much older neighbours...) Just interested in where you guys did the testing.

mikllaw

4-Nov-2010
8:57:20 AM

Away from the 2 'crags', on a 5m pile festooned with cars opposite 51 thomas mitchell drive. the bolt testing is in the 3rd quarry, above the barden ridge crag

mikllaw

4-Nov-2010
12:12:05 PM

The ratings we made on the gear have been released on
http://www.sanguma.org/destructo

Suffice to say they are pretty random. though they were generally conservative, we over-estimated the strength about 10% of the time, so back up your gear if "failure is not an option".

By a simple statistical correlation, I had the least accurate ratings of the gear's strength, so there.

mikllaw

4-Nov-2010
3:35:40 PM

On 4/11/2010 davidn wrote:
>The moral? "Trad, it really is a crapshoot, even if you've been doing
>it for ages"!

Too true!
But if your rack is big enough, you don't need big balls...

There are 111 messages in this topic.