Climbing partner

[mitchleblanc]

wait a minute- injection moulding is for plastics. Maybe it's cast- hmmm- that's cast iron though.

I think they could cold forge rings, no? Machine a ring out of steel and forge it into a ring?

And as for injection moulding, I am pretty sure they actually can inject metal. Of course, if so, I have my doubts they inject high strength steel.. just crap low temp materials. I would Google it, but I'm at a laboratory computer so... Wouldn't want to accidentally DL some porn. Yeah. Accidentally..

[Fred]

My bike was locked to a bike rack at the climbing gym here. It got backed over by some ass in an SUV that just drove off. The front end of my biked was smushed. The rack was ripped out of the ground from its expansion bolts and the heavy duty rack broke cleanly right at the weld.

I hardly doubt the weld for the bike rack was designed meaning the amount of weld provided was not enough to be stronger than the capacity of the tube/rack. So then clearly it broke at the weak point.

[Fred]

Yes Fred- approx 70,000psi depending on the particular rod that was used in the process and the base metal.

The positioning required to complete this particular weld and size of the ring makes it very difficult to do correctly. Very likely to be a cold weld with both porosity and slag inclusion.

You'd be surprised how many broken welds there are in the world of welding.

Material resistance factors in the engineering design world we live in today take into account pour workmanship. Meaning, weld capacities are reduced by a material resistance factor. For example. Steel is a very homogenous material so we (typicaly) use 90% of it's capacity. Concrete on the other hand has a lot more room for error so we typically use 60% of it's capcity. When you get into bolts and welds etc. they have their own reduction factors to ensure the outcome will be a solid design. When welds are crucial for safety and there is no redundancy, they are x-rayed.

As for welded rings such as the ones on "Fixe" rap anchors. I suspect they are manufactured in a perfectly controled environment. But I also wouldn't be surprised that the welds which close up the rings are made by machines for consistency.

I guess the point I'm trying to make is. I wouldn't say welded rings are unsafe. If we adopt that philosophy then there are plenty of other non-climbing engineering death traps out there.

[mitchleblanc]

It's hilarious to me that civil engineers use safety factors that we don't use at all in mechanical engineering. For example: the yield strength of steel is X, we use X. Civil engineers don't even talk about yield stress, they just have a strength value (I'm fairly sure). If you want safety factors, we built them in later, in terms of the stress on the part. Whether it's aluminum or steel is not really an issue. The "consistency" of a material is evaluated when determining the acceptable value for yield strength ..

It's essentially the same thing, obviously, but it's funny how the different fields use a different approach, because of their different backgrounds.

Is this an engineering forum? It should be!

[Fred]

actually no

without going in depth,
we do use 90% of yield stress for steel capacity. Yielding is considered failure.

[mike]

Fred- Other than pipelines- most stuff is batch tested with 10% of the batch examined unless problems are found.
While I agree that Fixe anchor rings are good to go... this thread is to unexperienced climbers asking for advice. I've seen some pretty beefy looking rings on bondage gear at the local sex shop. Oddly enough they look just like the ones Fixe makes. Also, it was either Mountaineering Freedom of the hills ed.5, or John Long's Anchor building book (I can't recall which and I don't have access to either book right now) that warned climbers about welded rings.

When I said avoid these rings, I was going on that advice.

As for the bike rack... the piece of tubing was probably butted up against the plate and welded around the perimeter. For a proper full penetration weld the piece of tubing would have to be beveled and held away from the plate a distance approx equal to that of the diameter of the welding rod and depending on the thickness of the two pieces there may be a need to heat both pieces before and after the welding takes place.

Mitch- I was thinking about that last night- I was thinking that they are probably stamped. I was also thinking that if they are stamped- what happens to the wasted material. Hmmm still thinking.

... and did you give up yer roll as the spelling police? You must be over worked, pour guy, I feel for ya!!!!

Muaaaaa Haaa Haaaa Haaaa

[Fred]

While I agree that Fixe anchor rings are good to go... this thread is to unexperienced climbers asking for advice.

Mike, I agree. I just didn't want other readers to start thinking that climbing hardware is not safe. Next thing you know you have people feeding their rope straight through bolt hangers to avoid using chain links which is probably more deadly in the long run. I think a good rule of thumb is... look at it and if it doesn't look right, it probably isn't. Or bring x-ray to the cliff and do a full test but might be a while before we get portable gizmos for those.

On another note. Chain yield stress is usually much lower than high strength steel bolts and hangers for climbing hardware. Thus, an old rusty chain loses capacity because of the rust but also is not that strong to start with.

SNAP!!!
Imagine the look on your face as you weight an anchor and all of a sudden it fails. That would suck eh?!

[mike]

I see that look a lot at work when someone has just stepped out over a 600' drop and their rappel biner boings into the proper orientation- always good fer a laugh.

As for portable x-rays... we use 'em all the time. I doubt that climbers would be too stoked about red danger tape with the nuclear sign on it being strung about the forest. Think of all the little critters with extra apendages.

http://www.irata.org -incase you were wondering

[mitchleblanc]

Man, if the spelling police tried to keep up with recent posts on this forum he'd have an aneurysm (sp?). It's like a drunken two year old ape with a keyboard in here sometimes.

[The Mitt]

Well I'm glad someone is out there trying to preserve the queens English, and comment on our terrible spelling. Please Mitch keep up the good work. Do you put that on a resume? or is it just for fun?

Mitt

[mitchleblanc]

Actually, the Queen Knighted me some time ago for my services to her majesty's Department of English (Punitive Division).

So it's "Sir Mitch" to you, and watch your tongue, heathen.

[mike]

UUUUUUUUHHHH OOOOOHHHHHH!!!!!

Someone just got their face bitch slapped with a velvet glove.

Ding! Ding!

LET"S GET READY TO RUMBLEEEEEEEEEEEEEEEEEEEEE!

Whooo Hoooo!!!!!!

[Nate]

Mitch,
Would you also "kick Cara's ass" if she belayed you on one locking biner?? What is the difference between one locking biner in the anchor and one locking biner on the belay?? or do you belay with two locking biners ...and two ATC's and two harnaress??
Nate
.....simply looking for a good telling off.....

[mitchleblanc]

Well, if you'd read my previous post, you would know that I said I would only kick your ass if you didn't back up the toprope, because it's *possible* to back up the top rope.

I would be happy to show you how to set up an anchor with no redundancy, if you want, then I wouldn't have to kick your ass or waste my time repeating myself for your benefit.

Just kidding. Backup whenever possible buddy.

[Fred]

oh man this would be a perfect time to revive our climbing lessons 101 eh Mitch?!