Thank you for you feedback. I'm a bit surprised because I buyed one too and is worked perfectly, just friction enough like actual lego piece. My guess is, because you're not the first one to tell, that shapeways smoothing process is more random than lego use to do. Some people think about the same piece axle are perfect, or too loose, or too thight. I don't know if there's a solution about this. Only thing I can recommand in your case is to not force the piece, or else it could broke. Maybe you can carve it just a little with a sharp tool to make it more suitable for you MOC ?