MPCNC: Guilloche Engraving First Light

A diamond point drag engraving bit in the MPCNC scratched a suitable Guilloché pattern into a scrap hard drive platter much much better than I had any reason to expect:

MPCNC - Guilloche 835242896 - HD plattter - 0.1mm
MPCNC – Guilloche 835242896 – HD plattter – 0.1mm

That’s with a 0.1 mm cut depth, sidelit with an LED flashlight.

Feeding those nine digits into the Guilloché pattern generator script should get you the same pattern; set the paper size to 109 mm and use Pen=0 to suppress the legend.

The same pattern at 0.3 mm cut depth looks about the same:

MPCNC - Guilloche 835242896 - HD plattter - 0.3mm
MPCNC – Guilloche 835242896 – HD plattter – 0.3mm

It’s slightly more prominent in real life, but not by enough to make a big difference. I should try a graduated series of tests, of course, which will require harvesting a few more platters from dead drives.

Either side will look great under a 21HB5A tube, although the disks are fingerprint and dust magnets beyond compare.

9 thoughts on “MPCNC: Guilloche Engraving First Light

  1. One step closer to producing your own luxury watches.

    1. On the scale I’m working, the watch would be a walk-in exhibit. Which, come to think of it, might be a spectacular Makerfaire attraction …

  2. Try acid etching them a bit if you’re not going for high gloss, they’ll probably stop attracting fingerprints. Or just spray paint them with matt clear coat

    1. Ah, but high gloss is definitely the attraction, despite the dust-and-smudge problem. If acrylic domes weren’t so absurdly expensive for what they are, I’d have ’em on all the tubes.

      1. Doug Jackson of SV Seeker fame did his own acrylic domes on the lathe, first turning them, then sanding and finally fire polishing. Don’t know how “absurdly” expensive we’re talking about her, but it’s definitely doable

  3. I’ve experimented with a diamond-point engraver on my small CNC mill, exclusively in brass though. My engraver came as a kit, with a spring-loaded holder for the bit, so depth of cut has a broad range where material properties are the primary driver. The one thing I found works great on brass – run the code twice, as the second pass will clean up some of the debris of the first pass. Also, masking tape works great to remove the “chips” – lay it down after etching, then rub and/or dab it around.

    1. I’m doodling a spring-loaded holder to fit the Sherline’s cramped Z axis, because it’s a whole lot more stable & repeatable than the MPCNC for fine patterns. Eventually, I’ll try two-pass engraving.

      Thanks for the suggestions!

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