I have to make a .625 radius groove in a block of 6061, about 14 inches long. Having never done this, I was wondering how to approach it. I know that typically you don't run large diameter end mills due to the stress on the machine and the run out and possible chatter you get from a tool holder vs collet. So my question would be, is there a form cutter I could use that I have not been able to find online, that would work and not tear up my mill? I found a Ball end mill in 1-1/4" but was pretty sure that's a bit large for my mill to handle.