Hello we are cutting and OD 1/4-18 NPT thread in 316SS currently with a 18 NPT threading insert from Sandvik. Would like to use and 18 UN threading insert instead so that the thread finish would improve. (not as sharp) Is this possible since the thread angle is the same, and would give a slight radius to the thread form. My question is will it still seal as well? Has anyone done this be for?