[bluGill]

If it is structural I'd buy from a big place not Ali. Unless you have the ability to verify the material really has the claimed properties you need you should stick with a major trusted supplier who will either verify the factory produces fittings to spec, or test everything for you.

[fidotron]

If it is to support a human I would tend to agree, but for desks etc. I have found local supplies (Canada) have declined in quality to such a degree they need the level of QA on arrival the Chinese ones do while costing 5-10x as much.

[bluGill]

unfortunately the big box stores do not check quality. mcmaster which was pointed out above does and is a similar price. I am not sure about granger.

[potato3732842]

Paying big bucks for a paper trail is almost never cost or time effective compared to just adding safety factor for "normal applications".

And by "normal applications" I mean "please nobody be intentionally obtuse and start nit picking about aerospace applications and connecting rod bolts and whatnot".

[night862]

I would nit-pick about your cantilever worktable failing because of a crappy fastener, killing your cat. Child even?

[potato3732842]

There will always be a weakest link. At some point you just gotta be an adult and not build things to within an inch of their lives for the use they will see and then have the self control to not push the limit. Resources are limited and engineering tradeoffs are everywhere. These discussions always devolve into absurdity very quickly.

[night862]

It just isn’t very absurd to worry that the question mark brand of load bearing fasteners are properly rated.

I avoid the issue by not buying them, a lesson learned from my experience working in the QA field. I wouldn’t expect a teenager to have learned this lesson.

[quickthrowman]

“Don’t buy fittings made from Chinese pot metal” is a simple way to avoid catastrophic failure due to substandard materials.

[bluGill]

I don't need the paper trail just the quality it provide. That is often available for much less.