A 0.5 mm Pilot V5RT pen produces good-looking results on presentation-grade paper:
Peering through a measuring magnifier shows a bit more tremble in the traces, but they’re still OK:
The desk light off to the upper left casts shadows from the reticle on the three different sheets.
A closer view of the linear scales:
The pen lines seem to be 0.25 to 0.3 mm wide, with 0.4 mm dots at the end of each stroke.
For comparison, the engraved lines on my trusty K&E Deci-Lon slide rule are under 0.1 mm:
The digits look like they’re embossed into the surface with shaped punches, rather than engraved like the lines. Of course, I don’t know how K&E’s production machinery worked.
A closer view:
I think 0.1 mm is an aggressively narrow trace width, even for a laser engraver.