In my years as a swiss machinist I havent been able to find any insert which will break stainless adiquately. Taking a smaller DOC will make it even worse. Even if you do get some slight breakage one time, the next material lot may not break at all. The only thing that I found works well consistantly is having a thin insert with a sharp edge and a deep profile which will make the material curl more and not be so long and stringy. The insert I like the most right now is actually designed for aluminum but also works great on some of the more "free machining" stainlesses. It is the Seco VCGT3251 ALKX. Another thing which always helps is making sure that you have lots of coolant not only flowing on this inserts themselves, but also pushing the chips down and away so they wont block the oil from the insert. I typically run around 3000rpm @ .0015ipm in 303 at that diameter and my inserts last all day! |