Not too familiar with bolt grades, but I have a need to replace the blade bolt on my John Deere riding mower. Apparently the tall grass was a little too tall for it, but instead of just stalling the engine the blade bolt sheared. First the gods smiled as I managed to find the washer and blade retainer in the grass, then the gods of broken bolts were favorable as I managed to extract the rest of it from the boss with a bolt-out (first time ever!). I am just in need of a replacement metric bolt, but wondered if I should look for a specific grade.