/ ice screw attachment

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Barry Kerwin - on 02 Dec 2012
Hi, Has anybody any idea how to get hold of the item detailed in the link? I have emailed the various addresses listed under contacts but to no avail.
http://www.climbingtechnology.it/en-US/climbing/ice/screws.html?idproduct=553

Thanks
Milesy - on 02 Dec 2012
In reply to Barry Kerwin:

Haven't see them. Just tie it off with a krab removed from one side of a draw, or use an "ice-scream" screamer.

http://www.needlesports.com/Catalogue/Rock-Climbing-Equipment/Slings-Extenders/Ripstop-Extenders/Ice...
GridNorth - on 02 Dec 2012
In reply to Barry Kerwin: I wondered when something like this would becaome commercially available. I once saw a group of continental climbers with every screw larksfooted off. It seemed like a good idea. Less chance of dropping the screw and fewer krabs to carry. I thought about doing the same until the information cane out from BD about the dangers of tying off ice screws. Grivel do a similar thing but cost a fortune as they combine screw, sling and krab. Can't see the point in buying a krab when I already have plenty but I like the look of these. Because the bit round the screw is a thin metal plate it is unlikely to weaken the screw.
In reply to GridNorth:
> I once saw a group of continental climbers with every screw larksfooted off. It seemed like a good idea.

Not really. The now rather old BD research found that tieing off screws that weren't fully in could lead to failure: http://www.needlesports.com/catalogue/content.aspx?con_id=095232e4-4caf-49ec-8495-9c9e00a633da I don't think anyone has since shown this to be wrong?

These metal widgets would stop that from happening, like with the Grivel speedys, but it's much better just to have the right length of screw. I've got two of the speedys - in real world situations the widget can easily freeze to the body of the screw and then the krab flies round trying to flick you in the face as you spin the screw home! Quite annoying.
NottsRich on 02 Dec 2012
In reply to GridNorth:
Because the bit round the screw is a thin metal plate it is unlikely to weaken the screw.


What do you mean by this?

Martin W on 02 Dec 2012
In reply to TobyA:

> The now rather old BD research found that tieing off screws that weren't fully in could lead to failure: http://www.needlesports.com/catalogue/content.aspx?con_id=095232e4-4caf-49ec-8495-9c9e00a633da

I don't think it really says that:

In the limited testing we have conducted with tie offs and various extensions clipped into the hanger, our data suggests that it is best to clip in directly to the hanger if the screw sticks out less than 5 cm. If the screw sticks out more than 5 centimeters, tie it off as you normally would.

In the few tests conducted with tie offs the average strength is near 2700 lbf/12 kN. The typical failure mode of tied off screws is that, after about 1500 lbf/6.7 kN, the screw flexes and bends causing the sling to slip to the head of the screw, resulting in high leverage. Failure is generally caused by the sling being cut by the edge of the hanger in the 2000 to 3500 pound (8.9 to 15.6 kN) range.
For the majority of placements this strength range is enough to hold typical falls. However, with a high impact force rope and a high fall factor, failure of the tie off could result. The best option is to simply place a screw of the appropriate length and not have to worry about tie offs altogether.

(All emphases are mine.)

They pulled each placement to failure anyway, they were just reporting the forces at which failure occurred.
GridNorth - on 02 Dec 2012
In reply to TobyA: I know, if you read the rest of my post you will see that I went on to say as much.
GridNorth - on 02 Dec 2012
In reply to NottsRich: I meant because the thin metal lays right up to the end of the screw and doesn't leave much protruding.
In reply to GridNorth: Sorry GN, obviously reading too fast! Well, at least the link is there to the research now.
In reply to Martin W: They cut the tie-offs on the hanger after bending the screws in some case as I understood it. So that failed - not the screw itself. Which is why a metal thing like this would probably stop that from happening, but I said in my post what you've also put here - better just to have the right length screws if at all possible (or clip the hanger still if most the screw is in).
GridNorth - on 03 Dec 2012
In reply to Barry Kerwin: A quick draw with one end passed over the screw would have a similar affect but I'm not sure that BD Express screws for example are engineered to accommodate this. Having said that a skinny dyneema QD would be right up against the bracket so there would not be much additional leverage. Any engineers out there with an opinion. I like the idea in principle but my cautious nature is holding me back.
design crisis - on 03 Dec 2012
In reply to Barry Kerwin:

Try Russ at Troll UK,
GrendeI on 03 Dec 2012
In reply to Barry Kerwin: Joe Browns stock Climbing Technology, maybe they can order you some in! ;)

If they do...let me know ;)
iksander on 03 Dec 2012
In reply to Barry Kerwin: You tried Joe Brown's? They quite often have CT stuff
NottsRich on 03 Dec 2012
In reply to GridNorth: Thanks!
ads.ukclimbing.com
Barry Kerwin - on 03 Dec 2012
In reply to Barry Kerwin:
Hi folks,
Many thanks for the info, Joe Brown's are on the task hopefully it will be a positive outcome, if so I will keep you posted.

Cheers

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