a perfect 90deg joint - 15mm Alu

[dsc]

Gents,

I don't have much experience in the field of Ali stiffness and / or load support, so I'm hoping someone here can offer some suggestions. Here's what I'm looking to put together:




and the main question is:

What's the normal procedure for joining two 15mm thick Alu plates to get a perfect 90deg joint? The drawing above shows two plates, which are 130mm wide and two M8 holes for 80mm bolts and a 5mm deep pocket. The load from the top on the horizontal plate will be around 2kg. Will this be enough to handle the load and still maintain the perfect 90deg, or will it flex? I've seen various z-axis designs and some use additional triangle supports on the corner, others don't (even when using rather heavy spindles).

Any help is massively appreciated.

Regards and Happy New Year
dsc.