What specific size cotter pin is used for the EGO Power+ 8" Edger Attachment EA0800?
I always use every part intended for any tool, especially power tools. Why waste time questioning an engineering design regardless how insignificant you may seem it to be. I play many sports and encounter lots of people questioning rules they feel isn't "appropriate". I tell them rules are meant to create a "level playing field" for all participants. Everything we do has rules, otherwise there would be endless chaos. And if you insist on not installing that cotter pin, you're legally liable for endangering others. This isn't just about you and your stubbornness.