Thanks Andy !
Bought some 5mm angle yesterday (as i thought it was 5mm thick), but that doesn't matter i guess.
Also bought some grubs, but will buy more from Ebay. The local retailer asked 60 eurocents EACH...
On ebay it's like 50 for 2 or 3 dollars.... ;-)
Furthermore i found some nice aluminium tubes of 48mm for my CNC project. But i won't pollute this topic with that.