Betsy
Old School Grand Master
For simplicity, I'd suggest 2x discs of Scandi-ply, the inner ring screwed through the back of the outer ring, an undersize hole through the middle to take a bar of silversteel and press the undersized hole onto the rod so it physically can not be moved by hand.. excuse my rudimentary sketch.
The larger you go with the flange, the more weight it would support, if you did want to belt and brace it, you could tap a thread into the back of the bar and insert something like this
..but i honestly don't think you would need it, i bet it would easily hold 50kg without.

The larger you go with the flange, the more weight it would support, if you did want to belt and brace it, you could tap a thread into the back of the bar and insert something like this

..but i honestly don't think you would need it, i bet it would easily hold 50kg without.