Two standards govern this. EN ISO 8062-3 sets tolerance grades for cast dimensions (DCTG), and ISO 2768 sets general tolerances for machined dimensions. A buyer qualifying a supplier asks for both.
We have not published our grades yet. What we can say concretely is that we have parts in production held as cast on critical dimensions: one of our brackets is cast to tolerances for a bearing fit and for pressure tightness, with no subsequent machining at all. That shows the limit sits further out than many assume — but it is an example, not a blanket guarantee.
The practical rule: put tight tolerances only where the function actually needs them. Five critical dimensions on a bracket is normal. Fifty is usually inherited from a drawing originally made for machining from solid.
How to state the requirement in an enquiry: give a grade and a standard, not an adjective. “CT 8 to EN ISO 8062-3 on cast dimensions, ISO 2768-m on machined” is a requirement we can price. “Good tolerances” is not. At the same time, mark which dimensions are functional — bearing fits, hole spacing, seating faces — and which are merely nominal. That marking decides how many operations the part ends up with, and therefore the price per part.
Remember too that the tolerance on a cast dimension grows with the dimension. A tolerance grade is not one number but a table where the band widens with the nominal size — which is why a requirement that is comfortable over 20 mm can be unrealistic over 200 mm on the same part. And where a dimension crosses the parting plane, the die closing tolerance is added on top; such dimensions should either be placed in one die half or machined.
The verification side — measuring equipment, measurement reports and first article inspection — is where we have the least documented in public, and that work is under way now.