a long time ago, someone posted a link to asite which explained all the metric and imperial and stainless bolt grades, it had white background and was very good but i can't find the link. anyone know it??

I posted this one: http://home.jtan.com/~joe/KIAT/kiat_2.htm
It has a white background and information on the grades, so chances are reasonable.

I find this one useful

http://www.pts-uk.com/prodrng.htm