On my 1440, I use a Shars .125" HSS parting blade and holder, in a BXA toolpost. I run 100-150 rpm, with about .0045 / rev feed on the cross slide. Just enough blade stick out to make the cut.
Thus far, from plastic to 2.5" 304, parting has been entirely drama free.
Thus far, from plastic to 2.5" 304, parting has been entirely drama free.