I agree with everything that red81 has written, but I'd add that the buyers are to blame too, they're forever wanting to pay less for parts. This is what fuels the need for crap to be sold for peanuts. I had the same issue with some brake drums, the supplier offered two options, pattern and best quality, sadly the 'best quality' were still poor quality and not round. They went back!
I want quality parts and I'm prepared to pay for them as I rely on the van every day.