You've clearly never done much aid climbing. I can get the pin to engage the hook on most biners merely by weighting the thing with my body and a full wall rack plus rope drag. Cannot open the damn biner till I take some weight off it. Somewhhere in the neighborhood of 300-400 pounds if memory serves.

DMT

hell, pick up just about any biner and pull with your bare hands. yea thats right. your eyes didnt fool you. the gate/notch moves---



---now how safe do you nancies feel.



---better go back to knittin.

The pin-hook engagement design on the oval biner apparently is the best and make it superior to all the other biner out there and this due to fact that during tensioning phase, the load ( B) is evenly divided along the both side ( A) of the biner .

However, the oval biner are weaker and have lower KN than r D shape biner cause the strongest part of the biner is along the axis line (C) but when oval biners are loaded , the forces are applied away from the axis line and more in center.

When D shape biners are loaded, majority of forces are applied in one side causing the lower part of the biner (D) to bend in an angle. Since the gate side of the biner is not fixed and has a gap (between pin and hook), the hook side (F) also move to an angle of its own causing the pin or the hook to not engage or even if they engage, they would pop out.

This problem becomes even worse when the applied tension on a “D” shape biner moves away from the axis line and stay in the middle on the biner or closer to the gate side.

Does it interlock the same way when you take a fall with load been applied in all direction ?

I think gr4t nailed the point. the pin is crucial. it should be weaker than a strait section of biner under a tension load. however, because on most modern biners the load is moved to the spine to concentrate the load on the spine and reduce the bending load. bending loads are typically difficult to support with nice sleek compact shapes. the lever arm to the elbows is reduced by putting the loads closer to the spine. because the gate and pin are farther from the spine, their lever arm is further and greatly reduces the bending load on the elbows. this is why biners are so many times stronger closed than open.

Also, i saw something about plastic deformation. this is called creep. when a material is deformed elastically, the strain increases nearly linearly with load. in elastic deformation, the material returns to its original shape. in plastic deformation, the material retains (most of) its deformed shape. creep occurs above a certain stress level. this is where the material deforms nearly elastically then returns to a slightly deformed state with the load released.

The above is a theory, i don't have experimental or numerical proof to back it up. i do have some engineering background however, but further analysis testing would solidify the above theory.

I was also wondering if anyone knew how most biners are made. i know DMM forges their biners which i think is spiffy. are most biners made from some kind of strait stock that is bent to shape?

...
Also, i saw something about plastic deformation. this is called creep. when a material is deformed elastically, the strain increases nearly linearly with load. in elastic deformation, the material returns to its original shape. in plastic deformation, the material retains (most of) its deformed shape. creep occurs above a certain stress level. this is where the material deforms nearly elastically then returns to a slightly deformed state with the load released.

...
I was also wondering if anyone knew how most biners are made. i know DMM forges their biners which i think is spiffy. are most biners made from some kind of strait stock that is bent to shape

Most biners are made in similar format from 7000 series aircraft quality aluminum.

That's nice fluff that sounds cool. Care to explain what it means to the lay-man?

No, go research it yourself and find out what I mean.

But you're the certified aircraft mechanic. I'm just a n00b.

Yapp, Graduated from Northrop Institute of Technology in 1986 with GPA of 3.25

Dingus

not realted to our topic here but interesting to read.

http://www.bstorage.com/...o/carab/agecarab.htm

Then you should have no problem answering the question, right?

Trench

I know what you are trying to do. You are trying interrogate me in front of the RC member of the juries by cross examining some of the stuff I have said in here to prove that MS is wrong which I do not mind as long as you support your pervious statements. Now, to help you out of this miserable situation, why do not you just take the leadership and buddy up with the rest of wabbit bashing party and take this matter one step farther to the RC management and ask them to completely delete this post cause you do not see any reliable data to satisfy you.

Don't cry, dude... I just wanted to know what 'aircraft quality aluminum' is. I guess you can't answer that.

Back to the original point then...

Have you any comments on the stress-strain plots I linked that show that gate contact increases the slope of the stress-strain curve by a factor of three? Is that not enough evidence to show that the gate of the carabiner significantly impacts the strength of the carabiner?

IMO, the notch (hook) design should be shaped much like what is shown on image A than B assuming you do not cut too much from the side of the hook.


[URL=http://imageshack.us][IMG]http://img166.imageshack.us/img166/8813/screenhunter001iw7.jpg[/IMG]

[URL=http://imageshack.us][IMG]http://img148.imageshack.us/img148/525/screenhunter002qz5.jpg[/IMG]

You already know what AC quality aluminums are therefore; I see no point of trying to explain or cover the area because it is to related to this particular topic.

As far as how strong the gate is or it can, well you make the gate as strong as its possible by using other materials such as different compound or other metals like Titanium but still, the two pins on the side of the gate and the hook on the biner side dictates how strong the gate is . You can modify the hook to engage with the pin and do a perfect direct pull test where you know for sure that you got 100% hook-pin engagement but I will guarantee you that biner gate will fail due to following causes;

1- Broken pin at the either side of the gate
2- By a crack at the hinge side of the gate which causes the gate to come off
3- Or by broken hook.

The way I see it, the pin and the little hook do nothing. Basically, they are both worthless and I am pretty confident that, this is the biggest Screw-up in the history of climbing gear design and yet, manufactures are still making them with the same problem

The pin does not interlock with the hook under tension period. If the hook is there to stop the gate from bending backward (extend travel) then they could just cut the notch and keep the hook straight like a regular Chinese key chain biners .

During static loads the spring makes your proposed modification useless.

During dynamic loads, you modification would prevent the nasty effects of gate flutter, only if the gate tries to snap open after the carabiner has stretched enough for the hook to prevent the pin from getting dislodged. I don't know if this would be the case, in most gate flutter events.

Trench

Answer me this

What is the purpose of the lock on a locking-biner ?

A-is to stop gate flutter
B- To prevent the gate/hook misalignment
c- I do not know what to say
D other reason like.......................

first: I'm not trenchdigger.
second: this is condescending.
third: when a lock is in place, flutter would be impossible, hence forcing the gate/hook into alignment.
fourth: what are you trying to prove at this point? Is it that a key lock designed gate is better? I think so. Let's stop talking around that, and just talk about it.

Key locks are better.