Hello,
You were absolutely right! I tried an old cutter and it didn't work to well (the acrylic melted to my cutter), and then I tried a brand new 2 flute cutter and everything worked out fine. Thanks for the help
Ok, a picture from my dust shoe so far. It is not finished of course (as you can see) but maybe you get the idea. I hope it will work. Tomorrow I will try to continue with it.
I only had 4mm acrylic but I wanted it to be thicker. So I glued 2 pieces together. It works, but isn't very pretty (you can see air-bubbles, and you can see the glue isn't everywhere). But for my dustshoe it is good enough (for now).