Given a machined cursor blank, clamp it into position:
You don’t want to clamp the cursor directly to the Sherline tooling plate, because the diamond drag bit would pass over two or three of those 10-32 screw holes which would, by the conservation of perversity, leave visible defects. In hindsight, I should have put a recess for an aluminum plate in there.
After a single pass at Z=-4.0 mm, add two strips of tape to protect the adjoining surface and scribble it with red lacquer crayon:
Peel the tape off:
Then wipe off the residue using a soft cloth wetted with denatured alcohol:
That looks much like the previous efforts. I’d like a more uniform trench, but I don’t know how to get there from here.
In any event, the hairline looks pretty good against laser-printed scales:
The new cursor is the lower one lying atop a laser-printed Pickett-style Circuit Computer:
Looks good enough to eat, as the saying goes …