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majid_sabet
Apr 26, 2007, 4:33 PM
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I ran in to few research documents in regard to ice screw placement and I recently watched a series of documentary films based on falling climber and the ice screw position in solid ice formation . I was wondering if you guys have any first hand experience with different ice screw set up (falling during ice climbing) and generally what you think about these three different positions and why one position is superior over the other two.
[URL=http://imageshack.us]
(This post was edited by majid_sabet on Jun 10, 2007, 9:35 PM)
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misanthropic_nihilist
Apr 26, 2007, 5:06 PM
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C is the best. "How to Ice Climb" says so. As long as the ice is good and the screw has 'agressive threads.'
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trenchdigger
Apr 26, 2007, 5:09 PM
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As usual, It depends...
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tradmanclimbs
Apr 26, 2007, 5:17 PM
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In general B is best. if Ice quality is really good then C will be the best but if the ice is that good then it is not a an issue anyways. If you are running the gambit of many diferent qualitys of ice then INMOP the best average placement is going to be B. It really does come down to each individual placement and your experience.
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crodog
Apr 26, 2007, 5:39 PM
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You would think that A would be best but I think what happens is the ice shatters at the top of the screw sometimes only leaving the bottom half embeded. Position C minimizes shattering.
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banjo_jon
Apr 26, 2007, 6:05 PM
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http://www.jjgeng.com/html/ice_screw.html
it depends
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majid_sabet
Apr 26, 2007, 6:20 PM
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banjo_jon wrote: http://www.jjgeng.com/html/ice_screw.html it depends
Interesting link, sound like it also supported "C" in most testing.
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brent_e
Apr 26, 2007, 8:33 PM
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if it were me i'd be trying to place a screw at an angle between c and b and i would do so in a the depression above A! lol 
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trebork2
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Apr 29, 2007, 11:15 PM
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I believe if you read BD's owners manual they give out with there screws it says "a" is the best for good ice and "b" is the best for not so good ice. Could just be me though.
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rocknice2
Apr 29, 2007, 11:37 PM
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trebork2 wrote: I believe if you read BD's owners manual they give out with there screws it says "a" is the best for good ice and "b" is the best for not so good ice. Could just be me though.
I fell one on a screw[which is enough for me] and The ice beneath the screw blew out. The screw held me albeit two feet from the ground but it held. Upon inspection of the screw about 2" of ice blew out which makes it weaker by terms of leverage. Placements like 'C' break less ice. This applies to modern screws only with aggressive threads.
edited for spelling
(This post was edited by rocknice2 on Apr 29, 2007, 11:38 PM)
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basilisk
Apr 30, 2007, 2:04 AM
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trebork2 wrote: I believe if you read BD's owners manual they give out with there screws it says "a" is the best for good ice and "b" is the best for not so good ice. Could just be me though.
you may wish to read the manual again. A is nothing more than a lever. that placement is pretty much designed to break the ice apart. the "official" number is place screws at a 10-15 degrees downwards angle. so somewhere between B and C.....in the depression above A, as Brent said
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reno
Apr 30, 2007, 4:10 AM
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trebork2 wrote: I believe if you read BD's owners manual they give out with there screws it says "a" is the best for good ice and "b" is the best for not so good ice.
Nope. A sucks, not just for the angle, but for the bulge in which it is placed. Outward bulges like that place greater tension on the ice, making it less solid. Ever swing your tools and plant your pick in such a bulge? Did it hold?
Mine neither.
In reply to: Could just be me though.
Yep. It's just you. 
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catbird_seat
May 4, 2007, 10:39 PM
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trebork2 wrote: I believe if you read BD's owners manual they give out with there screws it says "a" is the best for good ice and "b" is the best for not so good ice. Could just be me though.
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paulraphael
May 14, 2007, 3:48 AM
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It helps to look at how a screw works. It's not a nail; the holding power comes from the threads, which distribute the load onto the largest possible surface area of ice. The threads also happen to be well below the surface, where the ice quality is likely to be highest.
C. puts the axis of the screw closer to the direction of loading in a fall.
A. tries to use the screw as if it were a nail, or a picket; the threads aren't used, and the load becomes a shear load concentrated at the surface, on a small amount of ice (and the ice that's likely to be lowest quality, and in this case, at a bulge). This position only makes sense if the ice is so bad that you don't trust the threads. But if this is the case, the picket position is probably only slightly better. So don't fall.
It's very likely that you WILL encounter articles and instructions that recommend A. This is because up until ten or so years ago, everyone thought this was best. We know that B. and C. are better because of more recent testing.
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pyramid
May 22, 2007, 2:14 PM
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How bout don't think about falling.
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bob_54b
May 22, 2007, 2:33 PM
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BD says that A is best but when I"m up there putting them in, I tend to go with B...it seems more sensible to me anyway. I would avoid C unless it's really juicy ice. If the ice is hard and cold (blue) down to green even, the leverage at the ice lip could possibly bend or break the screw under a shock load.
It seems that with A you're relying on the threads an awful lot to hold the damned thing in the ice whereas with B more of the ice on the inside of the hole is holding the screw perpendicular to the load.
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paulraphael
May 25, 2007, 4:32 AM
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bob_54b wrote: BD says that A is best ...
They don't. Their official recommendation is B (simplest, easiest, most likely to be adequate in both good and bad ice.
their current instructions can be downloaded from this page:
http://www.bdel.com/gear/turbo_express.php
The research, though, shows that the downward angle is actually strongest in solid ice:
http://www.terragalleria.com/mountain/info/ice/bd-test.html
(reports by the b.d. engineer who actually conducted their research)
http://www.needlesports.com/advice/placingscrews.htm
(another series of tests that concluded the same thing, also with b.d. screws).
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northernguide
Jun 3, 2007, 6:15 PM
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Does anyone recall the 'study' that Climbing magazine did about 10-ish years ago? I think Duane Raleigh was involved. I think they found through 150 lb drop-tests that screws in position 'c' held best in most ice conditions.
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paulraphael
Jun 3, 2007, 10:44 PM
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northernguide wrote: Does anyone recall the 'study' that Climbing magazine did about 10-ish years ago? I think Duane Raleigh was involved. I think they found through 150 lb drop-tests that screws in position 'c' held best in most ice conditions.
Every study I've seen (probably 6 or 7 of them, including the ones linked above) has concluded the same thing).
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graniteboy
Jun 7, 2007, 11:28 PM
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Yeah, although "C" is best in perfect ice, I have rarely seen perfect ice over the last 30 years of ice climbing. Consequently, I tend to place more like "B" in many placements, and only place C in perfect ice. Showing again that judgement is much more important than following iron clad "rules" that will inevitably get you killed.
How about this thought though: a good long ice climbing fall often ends up in a snagged crampon and a compound femur fracture. With a Compound femur, you can bleed out and die in a matter of minutes. Perhaps that's a slightly more important thing to think about than whether B or C is a better placement, eh? I am constantly surprised at how the sport climbing generation thinks that ice climbing falls are hunky dory. And I know a few of em who have titanium rods in their legs as a result of that hubris  ....
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anykineclimb
Jun 8, 2007, 12:13 AM
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Nowhere else is the adage "The Leader must not fall" more appropriate than in ice climbing. 
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iceravines
Jun 8, 2007, 1:47 PM
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B is the first choice- would be hard to blow out, and A would be second. C - thats asking for trouble and I would try to straighten as best as possible if I had no options.
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skinner
Jun 8, 2007, 4:22 PM
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paulraphael wrote: It helps to look at how a screw works. It's not a nail; the holding power comes from the threads, which distribute the load onto the largest possible surface area of ice. The threads also happen to be well below the surface, where the ice quality is likely to be highest. C. puts the axis of the screw closer to the direction of loading in a fall. A. tries to use the screw as if it were a nail, or a picket; the threads aren't used, and the load becomes a shear load concentrated at the surface, on a small amount of ice (and the ice that's likely to be lowest quality, and in this case, at a bulge). This position only makes sense if the ice is so bad that you don't trust the threads. But if this is the case, the picket position is probably only slightly better. So don't fall. It's very likely that you WILL encounter articles and instructions that recommend A. This is because up until ten or so years ago, everyone thought this was best. We know that B. and C. are better because of more recent testing.
Bang on, I'm suprised how many people still think that a slight upward angle is the best placement. (in good ice) considering that it was proved otherwise almost 10 years ago.
Prior to this testing, everyone I know (including me) placed them at a slight upward angle (where conditions permitted) and had less faith in one that was placed in the now accepted downward angle.
Although.. there are a lot of other factors to consider..
Researcher: Jon Heshka
wrote: The reliability of an ice screw to hold a fall is somewhat dicey. Until recently, the prevailing orthodoxy had been to place the ice screw 15° above perpendicular. Tests conducted in 1996-1997 demonstrated, amongst other things, screws with aggressive threads hold best in good ice when set perpendicular to the ice or angled down to 20° in the direction of loading. The results also showed that the ice screw placement angle should be positioned above perpendicular in "less than great" ice. Factors affecting ice screw strength include compression and deformation of the ice, ice temperature, quality or hardness of the ice (plastic vs. brittle), number of thread turns over the length of the ice screw, the depth of the thread, shape of the thread, length of the ice screw, thickness of the ice screw wall and orientation of the hangar.
Here's a really good article that goes into detail on exactly how BD did their testing, what length of screw is the strongest, charts showing strength versus placment angle, and even what constitutes "good ice".
http://www.needlesports.com/...ce/placingscrews.htm
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breals
Jun 8, 2007, 5:03 PM
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i vote for b or c , a is no good. I personally place them straight in almost all of the time (b), sometimes c, but never a.
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shimanilami
Jun 8, 2007, 6:05 PM
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northernguide wrote: Does anyone recall the 'study' that Climbing magazine did about 10-ish years ago? I think Duane Raleigh was involved. I think they found through 150 lb drop-tests that screws in position 'c' held best in most ice conditions.
I remember that article distinctly. It stated that "A" is the best orientation, not "C". The basic logic was that "A" works like a screw and relies on the threads biting into the ice. "B" and "C", in contrast, act like a nail and rely on levering the ice, which was generally a bad idea.
It seems counterintuitive, which is why I remember it so clearly.
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