On 13/07/2019 16:39, alan_m wrote:
On 13/07/2019 10:28, Robin wrote:

An example of braces (and a strap which also adds rigidity) is here

https://www.arbc.co.uk/sites/all/themes/arbc/images/bench-kits/upended-bench.jpg


Cheap slatted benches with metal ends, available in many retail sheds,
seem to only need the central metal strap to keep the bench rigid.


I suppose that is because in order for the metal ends to go "off
vertical" the slats all have to become misaligned. And the strap goes a
bit of the way towards making the slats more like a solid sheet, with
shear strength. Slightly surprising, but if it works...