Hi, I am assuming you are using TCT router bits? If the tip just needs a slight sharpening of the edge or to remove minor burning/ resin build up then use the fine grade. Any nicks, small chips or other damage use the coarse grade, followed by the medium and then fine. No, the diamond sharpeners cannot be cut. You could consider E2522 if you wanted a slightly narrower sharpener. literally a few drops of water in use and then wash under a tap to remove any debris in the voids before next use.