My number is in error, but am pleased, as always, to incite comments.

I have two sets of form rollers, the originals at 2-15/16″, and another old set covered by Bingham at 3″ even. Both are within adjustment range, so on this model you can probably regrind 3″ rollers once or twice. That isn’t necessarily the case with other roller arrangements. I have no idea how an oversize roller will fit, even at 1/10″ over.
The older rollers are only covered for 17″ of their length, to use with stereotype chase.

Paul’s dimension for the diameter is substantially off–sort of close, but using 3.1″ would be seriously in error, and perhaps a typing mistake. When we have rollers made for our clients, the original Vandercook blueprints are used by the roller makers that we employ, and otherwise, we don’t share the specifications.

Fritz/NA Graphics

The diameter is 3.1″ I recommend NA Graphics to recover them. They have the original specs including, material, durometer, face length and position on the core.