In the early 60’s I worked in the toolroom of a firm making dies for alloy pressure die castings. I’ve also been involved with sand casting, but that’s all irrelevant. What is important, is to understand that the idea that manufacturers seek perfection is wrong. Perfection – or near – costs money and so the best engineer will make things just good enough for the purpose and no more. Which is why the castings you have aren’t perfect – there was no need for them to be. It is not a case of 'poor quality' but rather a need to be good enough but no more.
The sand castings (LM25) I get cast in the UK to my patterns have always been good – no inclusions, imperfections or pin holes. Likewise those castings (LM6) that we did in the 60’s, but as the latter were highly polished and seen, we took trouble over metal control and the casting process. But in both cases cost consideration came below finish.
