Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.
Tag: Improvements
Making the world a better place, one piece at a time
Tek CC – Milled PETG cursor – Lacquer-Stik hairline
This time, I had the clear film on top!
Although the picture doesn’t do it justice, the scales are in blue ink, which looks better against the yellow background. I suppose I could do custom colors:
Pilot V5RT cartridge – ink levels
The line width has decreased as the ink level drops: 0.3 mm on yellow card stock and 0.2 mm on glossy white brochure paper. I don’t know if they’re supposed to work like that, but, for this application, narrower lines are definitely better.
A separate instruction manual told you how to use the thing, under the reasonable assumption you’d be intimately familiar with slide rules.
In this day and age, the back should carry how-to-use instructions, so I summarized the manual into half a dozen lists:
Tek CC – instructions – first pass
Which looked fine & dandy & ready to print, thereby exposing various typos / inconsistencies / misalignments:
Tek CC – test print – HP Brochure vs ordinary copy paper
Whereupon I (re)discovered just how much paper matters.
The HP Brochure Glossy inkjet paper on the left produces wonderful results with a 0.5 mm Pilot V5RT ball point pen and has coating on both sides. It’s intended for handouts, brochures, and suchlike; the Pilot pens produce identical results on either side.
The same text, printed on plain old 22 pound “multipurpose” paper on the right, looks much better and makes the HP paper looks like something done with crayon on paper towel.
I could try a font with finer strokes, but … ick.
It’s unclear whether Brochure Matte paper would make any difference, nor whether running coated “inkjet” paper through a laser printer would have an … infelicitous … outcome.
Past experience shows the unsteady ziggurat of Linux printing doesn’t respond well to tweakage: when the default settings don’t work, there’s no easy / predictable way to change any particular setting.
For future reference, print the instruction on what will become the back of the bottom deck, mark the center point, tape it to the CNC 3018 platform, touch off XY = 0 at the center, and draw the front scales: everything lines up perfectly without extra fuss & bother.
Based on manually scratching some acrylic, the GCMC code retraced the hairline four times to help the Sharpie stick to the groove. Maybe fewer passes would be better?
Affix a PETG scrap to the milling fixture for some manual CNC action:
PETG – engrave through film
Just to see what happened, I made the first scratch through the protective film and, because it’s hard to tell which side is up, the scratch went through the white film.
Repeat several times with variations in number of passes & downforce:
The absolute best-looking line is at the top, with the diamond point scribing through the (white) protective plastic film.
Multiple passes average out the waves / glitches / irregularities, at the cost of broadening the hairline.
The bottom hairline suggests a single pass with more downforce produces a broader groove and a finer line of Sharpie ink at the bottom; the top appears more rounded and the bottom more ragged.
Doing one pass with enough pressure to cut through the thinner (?) transparent(-ish) film may produce a better overall result. This will require me to get the orientation right.
The Real Hairline in my K&E Deci-Lon slipstick is a smoothly engraved, neatly half-cylindrical, channel with a smooth thread of red (!) ink / paint / pigment laid along the middle. Obviously, my engraving hand is weak …
The nightmare scenario: engraving a smooth hairline groove, completely backfilling it with paint, sanding (that side of) the cursor smooth to leave the groove’s paint flush with the surface, then polishing the plastic back to full transparency. Even I agree that’s crazy talk, at least for a circular slide rule made with laminated paper decks.
The furry engineers in charge of maintenance laid several layers of branches along the breast of their dam:
Beaver Lodge and Dam – raised dam – 2020-03-31
Their pond is maybe nine inches deeper than a few weeks ago. The rail trail has little danger of flooding, even as the water creeps closer, because the roadbed is higher than the far shoreline.
After removing debris, flattening the top surface, and generally paying more attention to detail, the PETG sheet has much better adhesion to the fixture:
Tek CC – Milled cursor – cleaned fixture
This time, I traced the inside of a drag-knife cut cursor to extract the blank from the stock and, yes, used new double-sided tape under the lower white protective film on the PETG.
Fewer air bubbles means better adhesion:
Tek CC – Milled cursor – fixture adhesion
Spinning the 1/8 inch end mill at about 5000 RPM produced finer swarf at the Sherline’s maximum 609 mm/min = 24 inch/min pace, with less uplift. I suspect Moah RPMs! would be even better, constrained by melting the plastic into heartache & confusion.
Scribe the hairline with the diamond tool, ease the finished cursor off the fixture, scribble Sharpie into the scratch, and wipe
Tek CC – Milled cursor – second try
It’s Pretty Good™ when seen against an un-laminated bottom deck drawn with a Pilot V5RT pen:
Tek CC – Milled cursor – unlaminated bottom deck
The diamond point tears a slightly gritty path through the PETG, which then looks a bit more granular than a real hairline. I’ve been using four passes for emphasis; perhaps fewer would be better.
The Noto (“No Tofu”) font family includes nearly All. The. Languages., which is certainly a noble goal, but I’m just not ever going to need fonts like these:
./NotoSerifTelugu-Regular.ttf
./NotoSansBengali-Bold.ttf
./NotoSansGurmukhiUI-Bold.ttf
./NotoSansGurmukhi-Bold.ttf
./NotoSerifTamil-Regular.ttf
./NotoSansOriyaUI-Bold.ttf
./NotoSerifSinhala-Regular.ttf
./NotoSerifSinhala-Bold.ttf
./NotoSerifMalayalam-Bold.ttf
./NotoSansTelugu-Bold.ttf
./NotoSansAvestan-Regular.ttf
… and so forth and so on …
A bit of searching & listing identified the few I might ever use, so armor those against the coming catastrophe:
There seems no regex-ish way of picking those out; next time, I’ll recycle the list as a script.
With armor in place, remove the rest:
find . -perm -u=w -type f -exec sudo rm '{}' \;
Rebuild the font caches:
sudo fc-cache -v -f
Maybe do such things near the end of the day, when you’re going to shut down anyway, because you’ll want to restart any programs using fonts in any nontrivial way.
Making the desired fonts read-only may confuse the next update involving the Noto fonts, but this setup (Xubuntu 18.04 LTS) is getting old and maybe something else will happen when I get around to installing a whole new release.
As other folks have discovered, it’s straightforward to convert soft, soothing baby wipes into toxic sanitizing wipes by pouring harsh chemicals down the hatch:
AmazonBasics Baby Wipes
Ending up with the proper dilution, though, requires knowing how much liquid the wipes already have, so you can account for it in whatever recipe you’re following.
Gut a new package of wipes: 552 g total weight, with 80 wet wipes weighing 536 g, so the packaging amounts to 15.5 g and each wet wipe weighs 6.7 g.
Hang five wipes in the breeze for a few hours to find they weigh 9.2 g. They’re still slippery, because of all the aloe & Vitamin E & whatever else Amazon specifies for the mix, but they’re dry. One dry wipe weighs 1.8 g, so all 80 weigh 150 g.
The block o’ wet wipes holds 536 – 150 = 390 g = 390 ml of water.
Should you want a 70% (by volume) isopropyl alcohol solution, pour 0.7/0.3 × 390 ml = 910 ml of 99% alcohol into the package and let it settle for a while. Each wipe will emerge dripping wet, but that’s not entirely a Bad Thing. Perhaps it’d be a good idea to start by letting the block dry out for a while, re-weigh, then calculate the alcohol dose from the reduced amount of water.
Bleach dilutions for sanitation seem wildly varied, but the jug of 8.25% sodium hypochlorite on the shelf says 1/2 cup to a gallon, a 1:32 volume ratio. Starting with 390 ml of water-like substance in the package, pour 12 ml of bleach into the hatch, let things settle, then squish it around for good measure.
None of the dosages seem particularly critical, given the slapdash way everybody applies wipes.
You should, of course, conspicuously mark the packages, so as not to apply toxic wipes to sensitive parts of you or your baby …
The Smell of Molten Projects in the Morning 