Well I stumbled upon a vid on youtube that displayed a desktop CNC mill that is slightly smaller than the one I have with a square shoulder 1" diam, 4 inserts endmill eating up brass stock 0.3" deep 0.5" wide @12IPM. Obviously it engages from the side. I have never tried square shoulder but with my slightly more powerful mill and a good 1/2" carbide endmill I cant take 0.15" deep in aluminum at full 1/2" wide let alone 0.3" deep.. Is that SS end mill really that much more efficient for slotting and shoulder cuts? They are pricey but if this true I would get one of those.