Savage_Greg wrote on 12/31/69 at 16:00:10:Might be metal fatigue or some other metal issue, but you still have to wonder why it broke, now, after 11 years. Right?
Yes, it does make one wonder; why now? No apparent extra strain on it. My best guess is as you said: Mediocre metal quality giving in to fatigue. One of my many jobs, had me helping engineers stress test large truck frames in a jig with huge hydraulic rams pressing and twisting the frames constantly. Discovery: Most of our high strength steel and automatic weld failures happened where the welds hadn't been "dressed" well by grinding and polishing after welding. Leave the most tiny crack in anything, and eventually that is where the stress will tear it apart. Same with castings. It only takes one bubble or thin spot, and that piece is junk. But in non critical parts where someone's life doesn't directly depend on it, not all pieces get magna-fluxed, or x-rayed, so some bad ones slip through.
It happens anywhere, but Asian Mfgs of different countries have been varying degrees of bad to terrible about metallurgy in practice for a long long time.
Edit: OTOH, giving credit where due: Asia was far ahead of the west in metallurgy in ancient times, and they have had astounding artisanship in all materials for centuries.