Hey guys, i'm struggling here.

Trying to cut G1/4 thread in 316 on a lathe. My plates keep breaking no matter what i do. Tried 3 different inserts/cutting tools, nothing seems to work. It's got a quite a big pitch for it's diameter. Same goes for M16 thread. Always struggling with that too. Just wondering if any of you guys have a way to make it easier for me. The lathe is a Mazak QT10

Thanks in advance