Quick question.

The large 1203 burrs switched from cast to machined in the past decade. When was that? Did they start shipping with machined burrs, or are they only available as a replacement? What year used should I buy to ensure that it has machined burrs?

Thanks!

You cannot buy new, cast 1203 burrs from Ditting. You will receive nothing but machined burrs from them (at least in the USA, but very likely that is a global standard for the company, I don't see why USA would be any more stringent). If you traded in a pair of dull cast burrs and paid the lesser amount for a "replacement" set, you'd get the next equivalent, but sharp.

Example: You have a set of cast burrs that have been sharpened twice before, you send them in and they evaluate them to see whether they are still in spec. If they are, they keep them and send you a pair that are on their third and final sharpening. If you sent in a pair that had only been sharpened once, and they deem them suitable, (within spec for that level of wear) they'll send you a set that can be sharpened only twice more.