After the grinding I sand the whole piece with a small belt sander that attaches to my NSK E-max micromotor.
I use tape sort of like a ruler to help mark where the lines will be. I use a scribe and lightly trace along the edge of the tape, then remove the tape and put on a new piece to mark the next line.
All the lines have been marked. Without the layout fluid the lines would be much harder to see while I am working, and I doubt they would even show up in the photo.
I filed along the lines tomake them deeper. I could have used a graver, but I think I am better with a file than a graver.