Harbor Freight - Gems and Junk
Good to know on the extensions. Probably garbage in the metal casting, causing a gas pocket or contaminant, creating a stress riser.
Castings that go through forges are stronger, but if the casting has a piece of garbage in it or isn't degassed thourghally, it will not heat evenly in the forge, which completely defeats the purpose of a forged piece.
I'll stick with US quality control on forged stuff.