The Smell of Molten Projects in the Morning

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

  • Clearing the Overgrowth

    Clearing the Overgrowth

    Our morning task on clear days has been clearing a forsythia overgrowth along the north lot line; the branches tip-root as our neighbor’s bushes creep southward toward the sunlight. The process involves ramming a six-foot octagonal high-carbon / tempered / tougher than nails / rings like a bell steel bar (measuring a generous 1-1/8 across the flats) deep into the dirt under the plant, kicking a 4×4 inch block against the bar, pushing downward with all my weight to pry the plant upward until something deep underground rips, then repeating from all directions until enough big roots break and the mass tears out:

    Forsythia root removal
    Forsythia root removal

    Then it’s on to the next plant.

    The turmoil exposed a run of black PVC pipe along the lot line, although one end seemed firmly anchored. More excavation revealed a giant grape vine root growing around the pipe:

    Grape root around PVC pipe - top
    Grape root around PVC pipe – top

    I had to sever the pipe with an axe on both sides to free the root:

    Grape root around PVC pipe - side
    Grape root around PVC pipe – side

    The pipe originally carried water from the Mighty Wappinger Creek along the east lot line, 500 feet away and 70-ish feet down, presumably to water the previous owner’s plants. As far as I’m concerned, the remains of that pump will remain on the bottomlands forevermore, but at least we’ve cleared the remains of the plumbing.

    Mornings like that make writing CNC code look downright attractive, but I’m developing the cutest little biceps …

  • Tek Circuit Computer: Formula Layout

    Tek Circuit Computer: Formula Layout

    Although Inkscape can lay out simple text in many intricate ways, there seems no way to typeset mathematical equations, even the simple ones involved in the Tektronix Circuit Computer.

    So I entered the equations in LibreOffice’s math editor, zoomed in on each equation to the maximum 600%, whacked the little-used PrntScr key, cropped out everything except the equation, and saved it as a PNG file:

    Tek CC - Bottom Deck Back - FR formula
    Tek CC – Bottom Deck Back – FR formula

    Import the PNG files into Inkscape, fiddle with the line spacing to get enough room, and jockey everything into position:

    Tek CC - Bottom Deck Back - formula detail
    Tek CC – Bottom Deck Back – formula detail

    Bit of a kludge, but it looks Good Enough™.

  • Homage Tektronix Circuit Computer: Minimally Viable Product, Pickett Variation

    Homage Tektronix Circuit Computer: Minimally Viable Product, Pickett Variation

    This one came out just about perfect:

    Tek Circuit Computer - MVP - Pickett Edition - front
    Tek Circuit Computer – MVP – Pickett Edition – front

    The yellow decks may not be authentic, but they definitely look nice; think of it as an homage to Pickett’s Eye-Saver Yellow slipsticks.

    The rear has my how-to-operate hints:

    Tek Circuit Computer - MVP - Pickett Edition - back
    Tek Circuit Computer – MVP – Pickett Edition – back

    Laser-printing on “inkjet” paper worked fine, although this isn’t fancy Gloss-coated Brochure paper, and the text looks like it should.

    The cursor sports a two-pass hairline scribed at 330 g and filled with Lacquer-Stick paint:

    Tek CC - Milled PETG cursor - Lacquer-Stik hairline
    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
    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.

  • Tek Circuit Computer: Paper Matters, Redux

    Tek Circuit Computer: Paper Matters, Redux

    The back of a Tektronix Circuit Computer’s bottom deck carries instructions and information:

    Tektronix Circuit Computer - rear
    Tektronix Circuit Computer – rear

    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
    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
    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.

  • PETG Diamond Drag Engraving Tests

    PETG Diamond Drag Engraving Tests

    The hairline on the second machined cursor looks pretty good:

    Tek CC - Milled cursor - unlaminated bottom deck
    Tek CC – Milled cursor – unlaminated bottom deck

    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
    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:

    PETG - engraving test - overview
    PETG – engraving test – overview

    Manual jogging FTW:

    • 2 passes, 300 g, through film
    • 2 passes, 300 g, no film
    • 1 pass, 300 g
    • 3 passes, 300 g
    • 4 passes, 300 g
    • 1 pass, 260 g
    • 1 pass, 330 g

    A closer look through the PETG sheet, as you’d see finished hairline, with the scratches in the same order as above:

    PETG - engraving test - detail grid
    PETG – engraving test – detail grid

    They may be easier to see against a blank background:

    PETG - engraving test - detail plain
    PETG – engraving test – detail plain

    Or in a hairline’s natural environment:

    PETG - engraving test vs Testors sample
    PETG – engraving test vs Testors sample

    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.

  • Beaver Dam: Rising Water

    Beaver Dam: Rising Water

    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
    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.

    Go, beavers, go!

  • Tek Circuit Computer: Cursor Fixture Adhesion

    Tek Circuit Computer: Cursor Fixture Adhesion

    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
    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
    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
    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
    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.