Biner Flex

Discuss vertical caving, equipment, & techniques. Also visit the NSS Vertical Section.

Moderator: Tim White

Biner Flex

Postby Scott McCrea » Feb 11, 2010 1:11 pm

Here's a little video I shot last week of a carabiner flexing under the load of a caver rappelling. :woohoo:

Scott McCrea
SWAYGO
User avatar
Scott McCrea
Global Moderator
 
Posts: 3198
Joined: Sep 5, 2005 3:07 pm
Location: Asheville, NC USA
NSS #: 40839RL
Primary Grotto Affiliation: Flittermouse Grotto
  

Re: Biner Flex

Postby Chads93GT » Feb 11, 2010 1:22 pm

It is really supposed to do that? wowzors
User avatar
Chads93GT
NSS Hall Of Fame Poster
 
Posts: 2293
Joined: Jun 24, 2008 1:27 pm
Location: Missouri
  

Re: Biner Flex

Postby Amazingracer » Feb 11, 2010 2:12 pm

Its fun to watch the carabiners when some one is climbing up a rope. We have some older SMC D carabiners at Georgia Tech were the screw on the screw gate chatter when bouncy climbers are on rope, we cite it as the perfect explain as why you rig with the screw gate pointed down.
User avatar
Amazingracer
NSS Hall Of Fame Poster
 
Posts: 307
Joined: Jun 25, 2007 7:24 pm
Location: American Fork, UT
Name: Kyle Gochenour
NSS #: 58846
Primary Grotto Affiliation: Dogwood City Grotto
  

Re: Biner Flex

Postby Cody JW » Feb 12, 2010 11:03 am

I have heard of some people using steel biners on the seat or using two alum. locking,opposite and opposed on the seat attachment.I have never noticed the flex but have not looked.I only use steel on the main rig point.I have always questioned if aluminum biners of different brands and same diameter have strength ratings that differ much.Are Petzl stronger than SMC ect.?Or are they private labeled made by the same factory and have various brand names put on them.I used to work for a boat propellor manufacturer that made about 20 diffrent brands at the same foundry using the same steel mixtures.
It only takes one person to surrender a dog to a kill shelter ,but it takes many to rescue it.
User avatar
Cody JW
NSS Hall Of Fame Poster
 
Posts: 905
Joined: Oct 24, 2007 10:16 am
Location: Indianapolis In. USA
Name: Jeff Cody
NSS #: 23961
  

Re: Biner Flex

Postby graveleye » Feb 12, 2010 1:10 pm

Cody JW wrote:I have heard of some people using steel biners on the seat or using two alum. locking,opposite and opposed on the seat attachment.


I use two locking biners, opposed, to attach my rack to my harness. Probably redundant, but it makes me feel better.
ad astra per aspera

http://www.myspace.com/jamthecontrols

The views expressed in this post are not necessarily those of any organization I am affiliated with.

Become a sustaining member of the SCCI
User avatar
graveleye
Global Moderator
 
Posts: 2934
Joined: Mar 14, 2006 11:12 am
Location: Georgia, USA
Name: Kevin Glenn
NSS #: 57238RL
  

Re: Biner Flex

Postby Chads93GT » Feb 12, 2010 5:38 pm

i use a rapide. im not liking how when leveraged just right, a rack can shatter the screwgate on a biner.
User avatar
Chads93GT
NSS Hall Of Fame Poster
 
Posts: 2293
Joined: Jun 24, 2008 1:27 pm
Location: Missouri
  

Re: Biner Flex

Postby Scott McCrea » Feb 12, 2010 7:24 pm

Chads93GT wrote:i use a rapide. im not liking how when leveraged just right, a rack can shatter the screwgate on a biner.

I tried to get that to happen a few years ago. Couldn't even damage it. Even with a two person load. Ended up putting the biner in the vice and putting a cheater bar on the rack just to get the sleeve to crack. I would say this is a myth.

Now, if you leave the biner unlocked, then, you're in trouble.
Scott McCrea
SWAYGO
User avatar
Scott McCrea
Global Moderator
 
Posts: 3198
Joined: Sep 5, 2005 3:07 pm
Location: Asheville, NC USA
NSS #: 40839RL
Primary Grotto Affiliation: Flittermouse Grotto
  

Re: Biner Flex

Postby chh » Feb 12, 2010 7:26 pm

It depends on the carabiner, but sometimes if you load a locker with body weight and THEN screw it down it can be difficult to unscrew when unweighted. I've had this happen to me on several occassions. Biners will flex a little, some more than others. That action in the video I think is probably why wire gates came about, to reduce the likelyhood of gate flutter which can be caused by vibration like that in the video. Even more so when the rope is moving through the biner much faster, as in dynamic fall scenarios. Heck, with most of my biners you can force the nose to move a little just with your hands.
Rapelling is some of the easiest stuff you can do to your gear, aside from a truly still hang. Don't worry about it. But amazingracer is right....screw down so you don't screw up!
Your words of caution are no match for my disaster style!
User avatar
chh
NSS Hall Of Fame Poster
 
Posts: 522
Joined: Oct 4, 2005 3:21 pm
Location: asheville, nc
Name: caleb
NSS #: 55745
  

Re: Biner Flex

Postby chh » Feb 12, 2010 7:29 pm

Scott McCrea wrote:
Chads93GT wrote:i use a rapide. im not liking how when leveraged just right, a rack can shatter the screwgate on a biner.

I tried to get that to happen a few years ago. Couldn't even damage it. Even with a two person load. Ended up putting the biner in the vice and putting a cheater bar on the rack just to get the sleeve to crack. I would say this is a myth.

Now, if you leave the biner unlocked, then, you're in trouble.


I'd say you're absolutely right scott, except for the older plastic sleeved petzl ball locks. I've seen one of those broken. Probably why they moved away from that design...
Your words of caution are no match for my disaster style!
User avatar
chh
NSS Hall Of Fame Poster
 
Posts: 522
Joined: Oct 4, 2005 3:21 pm
Location: asheville, nc
Name: caleb
NSS #: 55745
  

Re: Biner Flex

Postby NZcaver » Feb 13, 2010 12:16 am

Scott McCrea wrote:
Chads93GT wrote:i use a rapide. im not liking how when leveraged just right, a rack can shatter the screwgate on a biner.

I tried to get that to happen a few years ago. Couldn't even damage it. Even with a two person load. Ended up putting the biner in the vice and putting a cheater bar on the rack just to get the sleeve to crack. I would say this is a myth.

I'm not sure how you configured your test, but it's my understanding the carabiner gate issue is with inward force not outward. I was told this has caused at least one accident with a rack, but I can't recall the specifics.

Take one of those J shaped racks and clip the eye into the carabiner and lock the screw gate. As you weight the rack and begin to descend, be sure to neglect to check your system one last time. If the rack has twisted around in relation to the carabiner (before being weighted), the eye could possibly hang up on the locked screw gate instead of orienting in a normal liner configuration. When weight is applied in just the right (wrong) way, it can take surprisingly little force to lever the gate inward even with the gate sleeve locked. Or so I'm told. I'm no expert, and I haven't actually tried this myself. There are known cases of the same issue with a figure 8 descender (click here), and this could apply to virtually any other device with a relatively small eye.

I virtually never use my J rack any more, and prefer to use a 10mm Zicral oval Maillon Rapide with my Micro Rack. It's light, and more compact than a carabiner. I use a carabiner with my Stop, and don't have any qualms about attaching a descender with a carabiner as long as people are aware of this potential issue and CHECK their rig.

PS Scott - I'm reminded of the excellent topic you started last year Rappel Test for Sudden Accidental Disconnect
After posting all this guff, I just realized much of it has already been discussed before. :doh:
User avatar
NZcaver
Global Moderator
 
Posts: 6315
Joined: Sep 7, 2005 2:05 am
Location: Anchorage, Alaska
Name: Jansen
NSS #: 50665RL
Primary Grotto Affiliation: CCG
  

Re: Biner Flex

Postby caver9999 » Apr 21, 2014 4:35 pm

Will Steel biners flex as much, if at all, as aluminum?
caver9999
Infrequent Poster
 
Posts: 4
Joined: May 18, 2013 3:39 pm
NSS #: 44784
Primary Grotto Affiliation: Pine Mountain Grotto
  

Re: Biner Flex

Postby hank moon » Aug 30, 2014 7:43 pm

Scott McCrea wrote:I tried to get that to happen a few years ago. Couldn't even damage it. Even with a two person load. Ended up putting the biner in the vice and putting a cheater bar on the rack just to get the sleeve to crack. I would say this is a myth.


At least one accident has occurred with a plastic-sleeve Petzl Ball Lock (see http://www.karstportal.org/FileStorage/ ... 61-013.pdf page 42). Might be the one referenced below by NZCaver and chh. It can be tricky to get the right configuration to cause breakage, but it's not a myth. I have witnessed several test sessions in which aluminum and stainless steel screwgate sleeves were broken under bodyweight.

See http://www.simplycircus.com/sites/defau ... Popall.PDF for a presentation on the topic that was presented at ITRS 2003. The diagrams might be useful if you want to try some additional tests of your own. See http://theuiaa.org/upload_area/files/1/ ... -eight.pdf for a report on the phenomenon w/figure 8s.

Is it improbable that this can happen in the field?

Yes.

Has it actually happened in the field?

Yes, multiple times, and with metal screwgate sleeves.

"Anything that can go wrong will go wrong"


hank


Image

hank
User avatar
hank moon
NSS Hall Of Fame Poster
 
Posts: 610
Joined: Sep 7, 2005 9:52 am
Location: Salt Lake City
  

Re: Biner Flex

Postby Scott McCrea » Aug 30, 2014 8:24 pm

Hi Hank, thanks for the links. I haven't looked at them yet. I have a bacon hangover. I'll look at them tomorrow. In the mean time, I did more testing with this topic and post it here: http://www.swaygogear.com/biner-vs-rack-lever/
Scott McCrea
SWAYGO
User avatar
Scott McCrea
Global Moderator
 
Posts: 3198
Joined: Sep 5, 2005 3:07 pm
Location: Asheville, NC USA
NSS #: 40839RL
Primary Grotto Affiliation: Flittermouse Grotto
  

Re: Biner Flex

Postby hank moon » Sep 2, 2014 10:54 pm

Scott McCrea wrote:Hi Hank, thanks for the links. I haven't looked at them yet. I have a bacon hangover. I'll look at them tomorrow. In the mean time, I did more testing with this topic and post it here: http://www.swaygogear.com/biner-vs-rack-lever/


Scott, you are welcome. Glad you got to the breaking point.

Now about that hangover - details, please?

hank
User avatar
hank moon
NSS Hall Of Fame Poster
 
Posts: 610
Joined: Sep 7, 2005 9:52 am
Location: Salt Lake City
  

Re: Biner Flex

Postby Scott McCrea » Sep 3, 2014 8:04 am

I had just returned from Baconfest. Details are on my facebook page.
Scott McCrea
SWAYGO
User avatar
Scott McCrea
Global Moderator
 
Posts: 3198
Joined: Sep 5, 2005 3:07 pm
Location: Asheville, NC USA
NSS #: 40839RL
Primary Grotto Affiliation: Flittermouse Grotto
  


Return to On Rope!

Who is online

Users browsing this forum: Bing [Bot]

cron