Track pins

[20387774]

I believe what you want to do with the pins is called "case-hardening". If you get the mild steel pins hot in a forge and then remove them and cover them in bone meal, the steel will take carbon from the meal and harden only the outside of the metal. You could mushroom or peen the ends when the steel was untreated, as well as drill a hole on the other end for a cotter pin. Then put them thru the heat process.

John