I'm struggling to calculate with any confidence the allowable shear force for a metric bolt holding two aluminium pieces together.
I only need an approximate figure, since I will allow a very large margin of safety.
Assume that the pieces being joined are sufficiently strong. Assume the bolt is threaded throughout its length. It is acceptable for the thread to be damaged, but no permanent deformation to the bolt core. Assume a single bolt holds the two pieces such that the pieces can freely rotate, but that they won't.
The two pieces being joined are are 5mm and 3mm thick. The bolt is M8 with 1mm thread. Assume the bolt is made of a weaker steel.
What is the value of the shear force for the above?
So far, the most progress I have made is by using this online calculator, but I think it's for tension strength. Nevertheless, the "proof load" comes out at 8.82kN for for "property grade" 4.6. I'm guessing the area strength is of similar magnitude.