Rusty Roller

It is no great challenge for a machinist to return your roller to
pristine condition by turning, grinding, polishing it back to a
smooth, true cylinder, albeit very slightly less in diameter than
previously - Probably both rollers ought to be treated identically.
However, if your rollers are “case-hardened” rather than hardened and
tempered all the way through, then the layer of hard steel on the
surface may be quite thin over the softer core. The one-tenth
millimeter damage you need to remove doesn’t seem like much, but
it’s probably best if you know at the outset whether you have case-
hardened rollers. There are probably lots of folks on this forum who
can tell you much more about case-hardening than I can - like how far
below the surface does the hardening typically go?

Good luck,
Marty in Victoria BC