Hardware Store Quick Link

Brian in SLC wrote: Not that I've seen. A few years back I grabbed a bunch of different size quick link/rapides and as cheap as I could find them. Sized from ~7.mm to 9.1mm cross section. Broke them on an Instron. They all failed by shearing the threads and none appeared to be "welded" per se. Ranges I got were 6754lbf at 7.1mm, 7062lbf at 8mm and 7442lbf at 9.1mm. What was interesting...and what I really wanted to see...was the next test. I cut completely through a new set of these cheap rapides with a bolt cutter right in the location that a rope would sit. So, really, about worst case if you came upon a rapide on an anchor. The rope or 12mm test pin pulled through the cut after 3-4X body weight load was applied. Yeah, things that make you go "hmmmm....". Cheers.

Well it´s all fairly irrelevant but;-
I´ve found quicklinks where the threads are held on by electroplating (a common industrial process, be welding and the others they are forged and rolled.
The 8mm electroplated ones gave out at about 8kN, the welded stainless ones a bit better.
In contrast a rolled thread stainless quickling from 316 fails at 6022kg, I tested some last week for certification.
For me it´s important because they have to be certified to hold 25kN, for just lowering-off it probably doesn´t matter at all. Just changes the price!

Well...what's the takeaway...?

I think there's folks that get wigged out when they run into "cheap hardware store" quicklinks in the field. If they aren't visibly busted, or, cut straight through (worst case), then, they'll most likely work just fine.

Even if the link isn't closed or tight on the threads...you'd need an enormous load to bust one of these cheap links. Way more than you'd ever see on rappel.

Anyhow, it was a rough test to show kinda how ok these crappy cheap links are.

We also tested a small quick link with a 6mm cross section. Used a loop of rope to fail the link and the link snapped in the body, rather than at the threads. Load at failure? 5900lbf.

I'm certainly not advocating running out and buying a bunch of $1 quick links at the dollar shop (like, ahem, I did in the town of Joshua Tree). But, its "interesting" information on these types of quick links.

Cheers!

Brian in SLC wrote: Not that I've seen. A few years back I grabbed a bunch of different size quick link/rapides and as cheap as I could find them. Sized from ~7.mm to 9.1mm cross section. Broke them on an Instron. They all failed by shearing the threads and none appeared to be "welded" per se. Ranges I got were 6754lbf at 7.1mm, 7062lbf at 8mm and 7442lbf at 9.1mm. What was interesting...and what I really wanted to see...was the next test. I cut completely through a new set of these cheap rapides with a bolt cutter right in the location that a rope would sit. So, really, about worst case if you came upon a rapide on an anchor. The rope or 12mm test pin pulled through the cut after 3-4X body weight load was applied. Yeah, things that make you go "hmmmm....". Cheers.

Let me see if I understand this, you cut the quick link completely through in the radius at one end, hung it with the cut end down, and applied force to a test pin/rope at that location, and you're surprised it took approx. 500 pounds to pull it through, effectively bending the quick link apart?

I'm not sure how that's relevant to climbing.

Your first test seems to confirm that the strengths are suitable for use as an anchor point. 8mm is close to 5/16" and 9.1mm is smaller than 3/8. Those all appear to be stronger than a typical hanger.

Brian in SLC wrote:I think there's folks that get wigged out when they run into "cheap hardware store" quicklinks in the field. If they aren't visibly busted, or, cut straight through (worst case), then, they'll most likely work just fine.

Thanks a lot.
For doing the work of that "extreme" test.
And for explaining it.

Ken