[spdbrake]

The 4.8 bolts are basically annealed steel.

https://www.engineeringtoolbox.com/s...es-d_1428.html

I buy from McMaster Carr a few times a month. Items are shipped same day ordered, up to 7:30pm EST.

https://www.mcmaster.com/fasteners/f...x-head-screws/
https://www.mcmaster.com/browse-fast...x-head-screws/