After going through 45g of black ABS and unbending my inperfect print-bed and LOTS of good hints from Bogdan Kecman I managed to get a reasonable print-quality on my RepMan 3D-printer this night.
There are a few things on thingiverse that I´d like to print before
starting to design my own objects. Particulatly the Dremel-microlathe seems cool.
But currently I have some issues with the STL of the female buckle-strip for the male one I already printed (after Bogdan cleaned up the bad STL with netfabb professional 4.4. The free edition should work too and YES, there is a Linux-version of it.).