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#14631 - 11/03/13 11:50 AM ice screw technology?
Dane Offline
WI6
*****

Registered: 10/17/08
Posts: 131
I am curious as to anyone's thoughts on this. Still trying to track down the original numbers/data that went with the pictures.

http://coldthistle.blogspot.com/2013/11/ice-screw-technology.html

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#14633 - 11/03/13 01:16 PM Re: ice screw technology? [Re: Dane]
Anton Offline

WI8

Registered: 11/09/07
Posts: 310
Loc: Calgary
Dane - I generally find your posts worth reading, but that was a waste of my time. Are you saying that we should all buy Grivel screws simply because 1 test (with no data!) showed that a "pizza" comes out with a Grivel screw?!? Further, your link to the transcript from Kennedy/Belcout/etc contradicts what you wrote about the screws (their point was that in "good ice" both were equivalent and each design compromises something). Anyway, enough of my own drivel... a little more homework would be worthwile next time before you engage people in a discussion.

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#14635 - 11/03/13 02:09 PM Re: ice screw technology? [Re: Dane]
iceadmin/Will Gadd Offline
WI∞
WI8

Registered: 11/01/07
Posts: 380
Yeah, I'm having a hard time following Dane's commentary too.

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#14636 - 11/03/13 02:37 PM Re: ice screw technology? [Re: Dane]
Dane Offline
WI6
*****

Registered: 10/17/08
Posts: 131
OK, fair enough. I haven't seen the actual figures in years on the pull numbers Grivel came up with. If they were ever published. I simply don't remember. Just came across the photos again recently and thought they were worth rethinking. Ignored the whole concrete thing early on as I simply didn't care. Sure don't care what others buy or use. Thought that was at least clear.

I don't think it is the placements in "good ice" that are important. Damn near anything will work well enough in good ice. It is the marginal placement and hard starts that I thought worth reconsidering.

Like a nail ya generally gotta bend a screw to get it to fail. More ice engaged by the screw to support it as in the pizza shear photo is gotta be better I would think than the simple core removal. Could be wrong, could be total bunk. Might not even be what is shown. Which is why I asked for your comments. More real world ice experience here than any where else I know of. I think I know what the concrete photos show. Tell me what you think they show..or don't.

We'll all have to assume the photos show like testing in similar conditions and concrete quality. Till proven wrong I generally accept any industry testing as neutral fact finding efforts.

My guess is these are photos of a straight up pull 90 degrees to the concrete surface. Or straight out if you were in the field on real ice. Which we all know isn't likely to happen. I don't see any hanger deformation on either the BD or Grivel test screws. Which tells me the pull strength straight out might not be all that high.
(edit) I failed to notice the holding/pull fixture for the hanger they have rigged for testing so I might be WAY off assuming it is a low number.

How about instead of a pissing match (which I am not interested in) between what is better BD or Grivel we have a discussion on the test and what we can deduce from the pictures, if anything?

I'm not trying to convince anyone of aything here. Just offering my own, admittedly limited, experience/observations. Still trying to get the printed test data that show go with the pictures.

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#14637 - 11/03/13 08:48 PM Re: ice screw technology? [Re: Dane]
Sylvain Offline

WI6

Registered: 11/07/07
Posts: 150
Loc: Canmore, Alberta
Food for thoughts...

If numbers (we don't have) are similar, I'd rather have just the screw pulling than the screw with a big chunk of ice attached to it.

Because, once you've fallen, the screw will be following the rope back to you. Would probably hurt a bit but not as much as the one with a chunk of ice...

My 3 rules of ice climbing;

1. Don't ever, ever fall
2. Climb with grace, fluidity and a strong ethic.
3. If rule #2 doesn't work, go back to rule #1, don't ever, ever fall...

Sylvain
_________________________
The "Old" French Guy

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#14639 - 11/03/13 09:55 PM Re: ice screw technology? [Re: Dane]
Dane Offline
WI6
*****

Registered: 10/17/08
Posts: 131
comment posted at the blog.

Anonymous said...
Without numbers it's impossible to interpret these tests. Some questions that immediately come to mind:

If the testers had a hypothesis about failure modes for different thread types: A) what was it and b) did they attempt to address that by changing the material properties of the concrete?

Did the testers pour and set the concrete around the screws or somehow drill the screws into the concrete? If the latter, how did they ensure no damage to the threads?

How many tests were run for each type of screw? What was the mean and standard deviation of the pull-out strength? Do those numbers correlate with failure mode? Related to the above question, did they start with a new screw every time or attempt to re-use the same screw?

So many more questions come to mind for this to actually be a scientific study, but those are just the beginning. Without some sort of quantitative data, any conclusions drawn from these images are purely speculative.


and the data from the testing..but in Italian...

http://www.cnsasa.it/storage/wcms_f/alleg/LPV_documenti/Articolo%20Viti%20Ghiaccio.pdf

This study was presented at the UIAA Safety Commission on 9-11 May
2007 in Munich.

The concrete used was the UIAA indicated
standard for this kind of test.

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#14644 - 11/04/13 08:05 AM Re: ice screw technology? [Re: Dane]
karel Offline

WI7

Registered: 12/31/07
Posts: 290
Loc: Calgary
Using my awesome Italian skills (none), the graphs at the end seems quite clear as to what the results of the study were:

Holding strength between BD and Grivel screws were very close, so holding strength probably shouldn't be used as a reason to buy one screw over the other - if you like one brand better because you like the way they go in, then use that to differentiate.

Generally, the longer the screw, the more it holds.

The angle of placement makes a slight difference, but perpendicular looks like it's the best.

These findings seem to directly contradict BD's assertion that in good ice a short screw is just as good as a long screw. Since I don't speak Italian though I can't really address their testing protocol and if their findings would match up with real world application on a frozen waterfall. For instance, I'm not sure why concrete is being used as an analogue for ice - I'm not convinced this is a good assumption, but I have no evidence to support that. You'd think a block of ice made in a freezer would be the natural choice for testing...

K

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#14658 - 11/05/13 12:00 PM Re: ice screw technology? [Re: Dane]
iceadmin/Will Gadd Offline
WI∞
WI8

Registered: 11/01/07
Posts: 380
These tests were in concrete. CONCRETE. They are in my view totally irrelevant unless you're placing ice screws in concrete. It's like doing a snow tire test on hot asphalt or something, interesting in a sort of, "WTF were they thinking?" context, but likely not super illuminating. Maybe I'll post a link to climbing ice with kitchen implements, the plastic spatulas worked better overall than the whisks.

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#14662 - 11/05/13 11:41 PM Re: ice screw technology? [Re: Dane]
ken wallator Offline
WI6
*****

Registered: 11/19/08
Posts: 93
Hey if true to the weird concrete test put some old snargs or some pre 80's salewa screws in some crete lets make this recipe complete.Like the kitchen stuff too funny-ken

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#14664 - 11/06/13 01:09 PM Re: ice screw technology? [Re: Dane]
iceadmin/Will Gadd Offline
WI∞
WI8

Registered: 11/01/07
Posts: 380
A rubber spatula in an ice screw hole isn't as good as a steel-handled one. The steak knife worked pretty well. Pilsener Pillar a few years back with Mr. Cory Richards.




Edited by iceadmin/Will Gadd (11/06/13 01:12 PM)

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#14667 - 11/06/13 03:06 PM Re: ice screw technology? [Re: Dane]
Dane Offline
WI6
*****

Registered: 10/17/08
Posts: 131
Nice Will.

Seems the UIAA had a reason for a specific type of concrete. Consistancy in the results I suspect. I'm not so quick to make light of the testing or the data.

"The concrete used was the UIAA indicated
standard for this kind of test."

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#14668 - 11/06/13 03:46 PM Re: ice screw technology? [Re: Dane]
iceadmin/Will Gadd Offline
WI∞
WI8

Registered: 11/01/07
Posts: 380
UIAA ice screw test: "The UIAA safety standard for ice screws only tests the mechanical integrity of the actual screw i.e. the hanger and tube components – not the strength of it's placement in ice (ice screws have to be able to withstand a load of 10Kn for the EN standard and 9Kn for the UIAA standard."

So, unless there's a new test I'm unaware of and that could be, they use concrete to test the strength of the hanger… I'll still want ice screws tested in actual ice, as BD and other companies do.

Here is some testing I believe has merit: [url=strikerescue.com/file_download/1]strikerescue.com/file_download/1[/url] strikerescue.com/file_download/1


Edited by iceadmin/Will Gadd (11/06/13 03:49 PM)

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#14684 - 11/07/13 10:08 PM Re: ice screw technology? [Re: Dane]
Mike Klapey Offline
WI4

Registered: 09/25/09
Posts: 25
Loc: Cochrane / Golden
you had me at "crack pipe or pizza"

i recall seeing some Petzl videos that illustrated the angle of placement, solid core vs hollow / air pocket ice, among other variables.
i like the fact that they actually tested the screws in ICE.

if you must learn to climb on the internet google the heck out of the subject and note as many perspectives and opinions as you can.
and based on how variable ice is, you can place a "bomber" screw then five minutes later she's partially melted out.

bottom line, as with most things in life i don't think there is a single right answer..............

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