As a Swiss and an owner of a Schaublin lathe I can give you the answer:
We have four official languages and MANY dialects – so it is no surprise that there are several correct answers. Also Schaublin is a family name that is spelled in two different ways: Schaublin and Schäublin (with the two dots on the a, if it cannot be displayed correctly)
– in the german speaking part of Switzerland many people pronounce the name show(er)-bleen. This is the correct local pronounciation if the name is written "Schaublin" (which it is in most sales literature, manuals etc.)
– in the german speaking part of Switzerland also many people pronounce the company name as shoy-bleen (a little bit like soy-bean but with a sh in the beginning and an additional l). This is the correct local pronounciation if the name is written as Schäublin (with the two dots on the a). And that is what the company does sometimes (or at least did). In some sales literature the company called itself not Schaublin S.A. but Schäublin AG (with the two dots).
– to make matters more complicated: The name has its roots in the german speaking part but the company itself is situated in the french speaking part of Switzerland. There the name is pronounced similar to the name of the composer Chopin (if pronounced in french). As close as it gets in English would be sho(rt)-bl(ue)-un where "un" is pronounced like the french word for one.
Hope this helps.