I have a tractor that uses three 5/8 bolts, 3 inches long with fine thread, to hold on the front wheels. With there being only three bolts, and this tractor being used to lift 1000lb hay bales, and other heavy stuff, I know these bolts need to be strong. I was surprised to find that the local tractor store did not have these bolts, and said they could not order just one bolt and nut. I went to a farm supply store where they had a large selection of coarse threaded bolts, and only a small selection of fine threaded. However, they did have the size I needed. Another farmer told me that I should always use a hardened bolt for this application. They did not have any grade 8 fine threaded bolts, but the one I bought appears to be a grade 5.
I say "appears" because I was not sure. When I got home I went on the web and found this site:
-OR- ASTM A449 Listed as - Medium Carbon Steel, Quenched and Tempered.
First, is this strong enough? I know it's stronger than a common bolt.
Second, what is the triangle for? Is that just a brand logo, or dies it mean something about the grade hardness?
It appears to be a hard bolt, but that's just a visual look at it.
Otherwise I'll have to wait until I get to the city and see if I can find something better.
Thanks for all help and advice.