Big thanks to everyone. There is no McMaster Carr here in Germany, but there are specialty shops that specialize in all kinds of screws. However, I would have to plan 2-3 hours driving time for 2x 15km across the city of Berlin. Ebay is more relaxed and cheaper. It'll be in the mail, and I'm in no hurry.
But thanks to everyone for your tips.
Greetings Andy