Just out of curiosity, are there any tool manufacturers that stock tools that are shaped similar to a barrel mill, but with a concave radius instead of a convex radius? (Basically a barrel mill with the cutting radius inverted inward.) Emuge has a decent selection of "Circle segment cutters" such as barrel mills and lens mills, but I don't see anything with a concave radius from them or any other manufacturers I've come across. I'm working on a part with a cylindrical feature that can only be accessed from the side of the feature. I'd imagine you could save a fair amount of time surfacing with such a cutter, but