I've tried every tool,wrench,chisel, hammer I've been told to use.what do I use to cut a sink strainer locknut off?
You can also find a dedicated wrench designed specifically for sink drain nuts. https://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=sink+basket+nut+wrench . I've also drilled perforations into the nut face and then tapped a old flathead screwdriver under the drill holes. The nut easily broke apart at the drilled metal openings.