This document isn't specific enough by itself to define anything. Without any details, dimensions, as to location of the application of the force, i.e. half the distance between the ends of the gate, it's open to interpretation.
Personally, I think of crossloading as any loading geometry other than loading along the major axis (axis with largest strength rating). I don't know if a formal definition exists. Therefore, in my opinion, all of the above...
This document isn't specific enough by itself to define anything. Without any details, dimensions, as to location of the application of the force, i.e. half the distance between the ends of the gate, it's open to interpretation.
Yah, exactly. That's my point. And presuming anything from this doc other than the rough definition of what "cross loading" means is a moot point. Discerning the true definition of what cross loadin is as defined by the strength rating (the OP's actual question) would require details about the testing procedure.
Personally, I think of crossloading as any loading geometry other than loading along the major axis (axis with largest strength rating). I don't know if a formal definition exists. Therefore, in my opinion, all of the above...
I concur with this. A "crossload" is any load that doesn't or can't use the maximum strength of the biner. That said, there is probably some element of "crossload" in most any fall - IE. there are no perfect loads. Luckily biners are very strong.
Tom Frost (the engineer who came up with the first modern aluminium carabiner) once told me that his feeling was that if someone could design a biner whose X-load was greater than 12 KNT (I think this is the number he used - it might have been higher) that there would never be a carabiner failure.
The point is that there is a number where biners won't fail. Someone who I know once told me that when they rope solo's they uses a steel biner to attach the Gri because it's so much stronger in the X-load.
I think the number represents it's weakest possible orientation. This is different for every design, so one generic majid-diagram cannot fully represent the entire pool.
Personally, I think of crossloading as any loading geometry other than loading along the major axis (axis with largest strength rating). I don't know if a formal definition exists. Therefore, in my opinion, all of the above...
I concur with this. A "crossload" is any load that doesn't or can't use the maximum strength of the biner. That said, there is probably some element of "crossload" in most any fall - IE. there are no perfect loads. Luckily biners are very strong.
Tom Frost (the engineer who came up with the first modern aluminium carabiner) once told me that his feeling was that if someone could design a biner whose X-load was greater than 12 KNT (I think this is the number he used - it might have been higher) that there would never be a carabiner failure.
The point is that there is a number where biners won't fail. Someone who I know once told me that when they rope solo's they uses a steel biner to attach the Gri because it's so much stronger in the X-load.
Best, Kim
I am not asking for terminology. I am asking to find out how the number stamped on the side of the biner is defined. Since manufacturers are putting a number permanently in the metal of the product, there has to be some well defined standard.
The other guys are heading in the direction I was hoping for, and I think they are bringing up good questions.
One nice biner is the DMM Shield. Superstrong and light, yet they can't do a typical crossload test since it reorients itself from minor axis to major axis. If that were always the case then the crossload strength would be the same as the major axis strength. Of course once in a great while something may cause the biner to get stuck sideways, but it seems this is much less likely than most other lightweight biners, including cheap knockoffs like Madrock made in China.
You don't, actually. Once the frame is notched and the gate aligned against the opposing pin, pressure pretty well keeps it in place for the test.
--ML
having spent more than a few afternoons giving people the factory tour at BD, I can honestly say I have never seen a biner "notched" to maintain its position in the dynamometer.
pins are indeed used, but I seem to recall the tech holding the biner in position while setting the machine under light tension, just enough to secure the biner. the door to the machine is then closed and the test performed to failure.
watching that shit break again and again can be a very educational experience, especially when witnessed in a controlled environment.
be sure to take the tour if you're ever in Salt Lake and have the opportunity to. Check with the retail store for their tour days/times... 2pm IIRC.
You don't, actually. Once the frame is notched and the gate aligned against the opposing pin, pressure pretty well keeps it in place for the test.
--ML
having spent more than a few afternoons giving people the factory tour at BD, I can honestly say I have never seen a biner "notched" to maintain its position in the dynamometer.
pins are indeed used, but I seem to recall the tech holding the biner in position while setting the machine under light tension, just enough to secure the biner. the door to the machine is then closed and the test performed to failure.
watching that shit break again and again can be a very educational experience, especially when witnessed in a controlled environment.
be sure to take the tour if you're ever in Salt Lake and have the opportunity to. Check with the retail store for their tour days/times... 2pm IIRC.
but in the end, you agree it is the centered measurement of green??
You don't, actually. Once the frame is notched and the gate aligned against the opposing pin, pressure pretty well keeps it in place for the test.
--ML
having spent more than a few afternoons giving people the factory tour at BD, I can honestly say I have never seen a biner "notched" to maintain its position in the dynamometer.
pins are indeed used, but I seem to recall the tech holding the biner in position while setting the machine under light tension, just enough to secure the biner. the door to the machine is then closed and the test performed to failure.
watching that shit break again and again can be a very educational experience, especially when witnessed in a controlled environment.
be sure to take the tour if you're ever in Salt Lake and have the opportunity to. Check with the retail store for their tour days/times... 2pm IIRC.
but in the end, you agree it is the centered measurement of green??
for controlled testing purposes, yes. the reality in the field is another matter all together, where any loading other than along the major axis will result in sub-optimal strength.
There is one thing you have not shown on your diagrams which will result in gear failure at much lower loads than cross-loading (as i understand it), that being a load along the major (or any, actually) axis where the 'biner is levered on its side (or spine) over a feature on the rock. Preventing such a situation must be kept in mind when installing bolts or placing gear, and when such situations cannot be avoided perhaps a secondary piece near the primary piece would be considered prudent.
You don't, actually. Once the frame is notched and the gate aligned against the opposing pin, pressure pretty well keeps it in place for the test.
--ML
having spent more than a few afternoons giving people the factory tour at BD, I can honestly say I have never seen a biner "notched" to maintain its position in the dynamometer.
pins are indeed used, but I seem to recall the tech holding the biner in position while setting the machine under light tension, just enough to secure the biner. the door to the machine is then closed and the test performed to failure.
<snip>
Here's the standard:
EN 12275:1998 Paragraph 5.3.2.1.4 Minor axis testing "In order to avoid movement of the loading pins during the test, grooves may be made in the body, in the gate and/or the gate-locking device to sufficient depth to ensure location of the pins. These grooves shall not be subsequently the cause of failure."
Regardless of "correct" crossloading, I wonder what the strength ratings are for the blue and red loads. It's my experience that in real-life scenarios, carabiners are often loaded the red way. i.e. right above the gate. This is especially true with pear shaped carabs.
(This post was edited by sky7high on Aug 23, 2007, 7:13 PM)
Regardless of "correct" crossloading, I wonder what the strength ratings are for the blue and green loads. It's my experience that in real-life scenarios, carabiners are often loaded the red way. i.e. right above the gate. This is especially true with pear shaped carabs.
well the green should be stamped on the biner. The red and blue are the unknowns.
For most biners, I bet the green is the weakest point. So, I feel pretty good if the biner slides to the blue or red positions.
[snip] For most biners, I bet the green is the weakest point. So, I feel pretty good if the biner slides to the blue or red positions.
Well, the red position feels a bit more sketchy to me, because the portion of the carab right above the gate isn't hooked or attached to the rest of the carabiner. If the carabiner is loaded across the gate, the gate is still attached to the carab through the hook or keylock at the nose, but the nose can be folded backwards and it won't have a hook attaching it to the gate.
I don't know if this is clear, I'll try to post an image later
(This post was edited by sky7high on Aug 23, 2007, 7:18 PM)
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