I've been involved with the Z133 committee for years but this is much later than when the biner trend started. The definition of what an autolock is came from another ANSI standard. A very good job of wordsmithing.

I have no clue exactly what the history is for not allowing screw gates. It seems to me, from using Stubai steel biners years ago, that they are more likely to jiggle open than autolockers. There has to be some testing out there by now. Every once in a while a piece of literature comes to light about some testing. Most of the testing seems to come out of Europe and is related to either sport climbing of some sort or rope access work.

Even though we're discussing this in a rec tree climbing forum the points are still valid. I have a [bad] gut feeling that a rec tree climbing guide/instructor would have a hard time defending the use of screw gates if it was shown that the opening of one lead to an accident. Even though there is no obligation for rec tree climbing to follow the Z it seems prudent to come as close as possible to the standard practices. Is there another field, rec or pro, that sanctions the use of screwgates for liffe support. I know that most all rock climbers use non-lockers for protection. That's a whole different situation and rope use _style_.

I would hate to hear about an accident that could have been prevented by using autolockers.

Originally posted by Tom Dunlap
I've been involved with the Z133 committee for years but this is much later than when the biner trend started. The definition of what an autolock is came from another ANSI standard. A very good job of wordsmithing.
Then I want to express my sincere gratitude for the work you and your team(s) did to help make tree climbing, esp. work related, safer.
Originally posted by Tom DunlapI have no clue exactly what the history is for not allowing screw gates. It seems to me, from using Stubai steel biners years ago, that they are more likely to jiggle open than autolockers. There has to be some testing out there by now. Every once in a while a piece of literature comes to light about some testing. Most of the testing seems to come out of Europe and is related to either sport climbing of some sort or rope access work.
I think you've nailed exactly what's troubling me - "...There has to be some testing out there by now..." One would think so. But since I can't find any reference to any testing done with screw locks in regard to tree climbing, it just imcreases my curiosity as to how screw locks got such a bad reputation.

What I fear is that there really hasn't been any testing, and hence ANSI standards were not _base_d on test results and were _base_d on word-of-mouth. While I respect the opinions of experts and professionals, without at least some competent testing they are simply isolated events and they could be simply due to lack of training or human error. The real problem is these things get passed on and on and changed slightly each time it is re-told.

Originally posted by Tom DunlapEven though we're discussing this in a rec tree climbing forum the points are still valid. I have a [bad] gut feeling that a rec tree climbing guide/instructor would have a hard time defending the use of screw gates if it was shown that the opening of one lead to an accident.
I agree! In fact, even though my climbing will be rec climbing, I still have a desire to follow the ANSI standards. Where the conflict comes for me, personally, when I first got into climbing, I bought and auto-lock and a screw lock and started devising tests to see if one had any significant advantages over the other, and to be perfectly open, I was pulling for the auto-locks all the way. One day I was sitting in my easy chair with my biners and a piece of rope just playing, tying knots, etc. and I put a half turn around a auto-locker, pulled it and it readily openned and released the rope! I was stunned. I did it over and over thinking I was missing something. I mean all kinds of people use this biner, surely it really isn't this easily defeated. So I thought, I wonder if a screw-lock will do that. I tried numerous times and couldn't make it do it. So I decided right then and there that auto-lockers are dangerous and I'm using only screw-locks.

Then I read the ANSI standard and was shocked to see that screw lockers were not approved. Thanks to this board I learned about double locking, auto-lockers. So I bought three of them. But again, I can open them almost as easily as I could my original auto-locker.

So there's the conflict for me. My simple tests disclosed to me that screw locks were the more reliable, yet now I learn screw locks have a bad rep and nobody has any hard evidence as to why they do.

Originally posted by Tom DunlapI would hate to hear about an accident that could have been prevented by using autolockers. Again, I certainly agree with that sentiment, but also again why do you have the impression that the screw-locks are more likely to cause an accident than an auto-lock?

I'm just asking, I'm bewildered by all this. I want to be safe, in fact as safe as possible, but my personal testing reveals just the opposite of what the common thought is.

Way back, teachers were considered infallible. They used logic to project knowledge. For example, they deduced that because people had 32 teeth, horses also had 32 teeth. They were so confident of their logic that they didn't even bother to count the teeth in a horses mouth and taught it the way their common logic dictated. One day a student had the nerve to actuall count the teeth in the horses mouth - guess what he found? A horse doesn't have 32 teeth like he had been taught. When he reported this to his teachers, he was severely reprimanded and punished.

I'm not saying that's where we are by any means, but it does illustrate how things can get propogated without sound basis.

Any thoughts?

Here's my reductionist analysis of the screwgate versus autolocker question.

First:
Many tree climbers use screwgates. They are not intrinsically unsafe.

Second:
While you may be able to get a piece of cord to open an autolocker in the "lab", the collective experience of tree climbers is that well designed autolockers have not opened and caused a climber to fall. If anyone has heard of such a reported incident let's hear about it. It's worth noting that having the gate open will not guarantee that you will fall. Especially if your rope attachment is cinched on the biner.

Third:
I'm guessing, only guessing that the reason screw gates are not recommended is because of the opportunity for operator error, that is, forgetting to manually lock the gate.

In conclusion, I would weigh everything you've heard, climb low and slow, try your screwgates and make your decision. Ultimately we are all guided by our own judgement and responsible for our own decisions Every piece of gear has a potential loophole. As a new climber you have to either rely on your own gradual process of building trust in your gear and technique or rely on the experience of a teacher or mentor to help you make those choices.
-moss

Originally posted by moss
...
Third:
I'm guessing, only guessing that the reason screw gates are not recommended is because of the opportunity for operator error, that is, forgetting to manually lock the gate.
-moss
That's certainly one of the strong points for auto-lockers. I've forgot to lock one once myself. And that may be the best reason to use auto-lockers.

Ron,

Why don't you take this opportunity to solicit some feedback comparing biner closing mechanism tests on http://www.treebuzz.com/ and see what you find out.

not once in 15+ years of rope use in a variety of fields have i ever had a screwgate carabiner come undone. I can understand that NOT EVERYONE will check their biners before during or whenever on a treeclimb, but i have 100% confidence in a screwgate for treeclimbing. Work is another issue, i will use rope snaps because i have to.

I have hade ropes end up in sich a way around a double locker biner, that the outer part of the gate has slid down, and the gate was susceptible to being pushed open by rock, limb or another rope (under tension). That being said, I agree that a double action locker biner should be used by those entering the treeclimbing realm (treeworld), and that screw_link_s (i'm talking Maillione Rapides ONLY, not screwgate biners) should only be used by experienced on rope persons, who check and recheck their gear frequently before , during and after a climb. Too easy for someone with little or some experience to forget to check a screwgate Biner.

I happen to love the Maillione Rapides, the large 16mm pear is one of my favorite (and cheap $$$) rigging items. I can get the large pear for 12 bucks, it solves many rigging problems for me , by allowing webbing slings to be spread out and not contact each other.

one thing that does bug me is a lot of people are under the impression that if someone uses anything other than a double locking biner, they are putting their life at risk, and that the screwgate or Maillione rapide will somehow fail up the aire, and the on rope use will fall. I'm dealing with now at work. They are used to double locks only, and have this weird fear of anything different.