Machine Shop

Tek Circuit Computer: Cursor Hairline

Given a machined cursor blank, clamp it into position:

Tek CC Cursor - cursor hairline fixture
Tek CC Cursor – cursor hairline fixture

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:

Tek CC Cursor - tape color fill
Tek CC Cursor – tape color fill

Peel the tape off:

Tek CC Cursor - tape removed
Tek CC Cursor – tape removed

Then wipe off the residue using a soft cloth wetted with denatured alcohol:

Tek CC Cursor - red cursor detail
Tek CC Cursor – red cursor detail

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:

Tek CC Cursor - red cursor white laser decks - magnified
Tek CC Cursor – red cursor white laser decks – magnified

The new cursor is the lower one lying atop a laser-printed Pickett-style Circuit Computer:

Tek CC Cursor - red cursor yellow laser decks - overview
Tek CC Cursor – red cursor yellow laser decks – overview

Looks good enough to eat, as the saying goes …

3 thoughts on “Tek Circuit Computer: Cursor Hairline”

  1. Just thinking out loud, I wonder if heating or cooling the material would affect the smoothness of the cut for the hairline.

    1. It’d surely affect the overall glossy surface finish! When I tried heat-forming some thin polypropylene sheet, it was never the same again.

      Now that you mention heat, though, perhaps embossing a line with a heated blade might work.

      A razor would surely make a too-smooth V notch that wouldn’t hold pigment, but a flat-edged sheet of very thin shimstock might produce a square-ish channel with maybe a ridge along each side. Either would look better than the ragged scratches I’m so proud of.

      Thanks for the suggestion!

  2. Pingback: Tek Circuit Computer: V Engraved Hairlines – The Smell of Molten Projects in the Morning

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