Re: fender lsr roller nut
Ditch the whole thing. They are junk in so many ways. No adequate harmonic damping, unable to accept multiple string gauge options, increased friction caused by the little rubber block behind the ball bearings which is there to provide the harmonic damping which would otherwise be totally absent, no individual string height adjustment...
Take it to a good technician and ask him or her to rebuild the fingerboard and fit a conventional nut.