#engineering
// 35 posts tagged
Jul 9 7:42 PM #189 4 min The Nose Must Outweigh Everything the Wind Can Grab
Model RocketryA rocket flies straight for one reason: a pea of clay in the nose. Get it wrong and you've built a very expensive lawn dart. So I swung mine on a string, like 1960 told me to.
Jul 5 8:31 PM #154 day 2 3 min Four Grams of Sugar and the Pressure of a Car Tire
Kombucha BrewingLast month the culture died in eight seconds. This month it's alive and quietly building enough pressure to turn a swing-top bottle into shrapnel. Progress, technically.
Jul 3 7:30 PM #183 3 min Eighteen Hundred Spectra and Not One Photograph of the Sun
SpectroheliographyA good session leaves me with 1,800 spectra and zero photographs of the Sun. The photo is something you compute afterward — one curved pixel-column at a time, dust stripe included.
Jul 1 7:18 PM #181 6 min Add Metal Where the Probe Should Vanish
Microwave InterferometryMeasure by inserting a probe that disturbs what you're measuring, then tune it out with an adjustable stub.
Jun 30 8:49 PM #180 6 min Twenty-Three Where Fifty-Three Appeared
Thermal Expansion InterferometryCounted fringes to nanometre precision. Aluminum's expansion coefficient: 53 where it should be 23. The bench was expanding too.
Jun 29 5:13 PM #179 11 min Six Million Hertz Minus What the Coating Weighs
Optical Thin-Film Coating DepositionA 1 Hz frequency drop means 0.06 nanometres of coating. You're manufacturing precision optics by watching a crystal oscillate slightly slower.
Jun 28 4:28 AM #178 6 min Twenty Grooves Where Two Thousand Should Be
Diffraction Grating RulingCommercial gratings cost $347. Ruled 20 grooves by hand with a diamond stylus and a bent paperclip spring. Only 7,480 grooves to go.
Jun 27 2:55 AM #177 4 min Seven Tenths Where One Focal Length Should Be
Telescope Eyepiece ModificationOne of the $15 estate sale eyepieces was rattling. By 2:47 AM I'd disassembled five of them and couldn't stop.
Jun 24 5:47 PM #173 6 min Eleven Forty-Seven When the Wire Disappeared
Optical PyrometrySame colour, 250°C different readings. The pyrometer doesn't measure truth—it measures the same calibrated lie every time.
Jun 22 6:47 PM #171 5 min Ninety Degrees Before the Twist Snapped Cold
BlacksmithingHot steel rings like a tuning fork. Cold steel sounds dead. The 100°C difference between them is whether your twist flows or snaps, and you're reading it by ear.
Jun 21 5:32 PM #170 4 min Eighteen Centimetres Down to Robertson Number Two
Magnetic Gradient SurveyingNanotesla-precision magnetic gradient survey for buried foundations. Found a Robertson #2 screwdriver from 1978. The method works perfectly.
Jun 20 4:04 AM #169 6 min Zero Point Three Two Until the Aluminum Said Otherwise
Ground Penetrating RadarThe radar said 0.32 metres. The aluminum plate I buried said 0.40. One of them was lying, and it wasn't the metal.
Jun 19 5:12 PM #168 5 min One Point Eight Metres Where the Ice Left Clay
Seismic Refraction MappingStruck a steel plate with a sledgehammer to find out what the Victorians buried under my garage. The answer is clay. Lots of clay.
Jun 18 10:55 AM #167 3 min Thirty-Three Kilograms Before the Motherboard Goes Under
Mineral Oil PC SubmersionWent for calcium supplement, left with an acrylic tank to drown a motherboard in. Thermal stratification turns out to be harder than the hardware.
Jun 13 7:16 PM #163 3 min Four Millimetres Today Three Centimetres by December
Coral Fragment MicropropagationDropped a coral fragment by accident. Turns out that's the entire propagation technique—Dr. Vaughan discovered it the same way in 2006.
May 29 7:52 PM #150 5 min Seven Days Before the Charcoal Tells Me What the Soil Exhaled
Atmospheric Radon MappingThe Geiger counter that couldn't find meteorites now measures invisible radon seeping from rocks. Eight buried canisters wait to tell me what the soil exhaled.
May 22 8:12 PM #142 4 min Four Metres of Accuracy Around a Film Canister
GeocachingThe GPS insisted I was standing on top of it. I'd been staring at decorative boulders for twenty minutes.
May 21 6:54 PM #141 4 min Six Centimetres of Silver Into a Gap I Couldn't See
Bicycle Frame BrazingMarc heated steel until silver disappeared into gaps I couldn't see. This is either physics or magic, and I'm not sure the distinction matters at 650°C.
May 19 6:13 PM #138 day 2 5 min Nineteen Hours to Leather-Hard, Twenty-Seven to Scrap
Pottery Wheel ThrowingThumbnail test said leather-hard. Loop tool said otherwise. By 10:47 the bowl was scrap and Diane was explaining why trimming can't fix what throwing broke.
May 2 7:37 PM #124 5 min Three Point Two Microvolts From a Single Breath
Thermocouple Lace MakingBreathed on the lace, got 3.2 microvolts on the oscilloscope. Every junction where copper crosses bronze is a thermocouple. This was supposed to be decorative.
Apr 1 8:36 PM #90 4 min Twenty-Five Turns for Every One the Speaker Needs
Vacuum Tube Audio Amplifier BuildingA 5-watt Class A amp draws 30 watts from the wall. The other 25 become heat. Audiophiles call this warm.
Mar 30 8:01 PM #88 4 min Eight Hours Before the Brass Remembers Flow
Espresso Machine RestorationThe eBay listing said it smelled of mould. The listing was accurate.
Mar 27 7:31 PM #85 2 min She'll Eat Her Own Wings When She Gets Here
Ant KeepingA founding queen digests her own flight muscles into eggs. I have an empty test tube and a wait until spring.
Mar 23 4:44 AM #81 4 min The Blank Remembered It Was Glass
Telescope Mirror GrindingTarget tolerance: 50 nanometres. My grinding stand was off by 3mm. The blank lasted twenty minutes.
Mar 9 6:04 PM #64 2 min What the Creases Already Knew
Origami EngineeringI spent an hour arguing with a theorem about paper. The paper won.
Mar 3 8:51 PM #60 4 min Twelve Dollars, One Kinked Spiral, and Fifteen Teeth Untouched
Mechanical Watch DisassemblyThe seller called it "parts only." I called it a twelve-dollar curriculum in precision.
Feb 28 7:24 PM #60 4 min Seventeen Jewels and One Hairline Fracture
Mechanical Watch DisassemblySeventeen jewels. That's what the caseback promises, stamped in a circle around the Swiss cross.
Feb 19 5:31 PM #46 4 min Three Cups, One Wobble, and a Northwest Gust
Mechanical Weather Vane InstrumentsPerfect day to build a device that measures exactly what I'm already annoyed by.
Feb 18 10:00 AM #45 4 min Eighty-Five Teeth and Mars Still Drifted
Orrery Clockwork Escapement PrintingEighty-five teeth for Mars. Forty-five for Earth. A fishing sinker doing orbital mechanics on my workbench.
Jan 31 8:05 PM #30 3 min The Bearings That Learned to Hold My Coffee
QSO Radial VOR Dial CoastersThirty hobbies in, and I keep asking the same question: where did that signal come from? Now my coffee mug rests on the answer.
Jan 28 8:40 PM #27 4 min The Bishop Finally Admitted It Had a Back Lobe
Antenna Pattern Chess SetThe rook has a back lobe. When I pick up the bishop, I can feel the null. That sounds absurd. It is. I don't care.
Jan 27 4:00 AM #26 3 min Stitching the Sky While the Payload Keeps Talking
Stratospheric Telemetry Panorama StitchingA protocol invented for tracking horses now tells my balloon when to photograph the edge of space. This seems fine.
Jan 23 7:24 PM #21 3 min When the Flyby Learned to Hum Its Own Speed
Propeller Doppler ArpeggiatorWind from the northwest, gusting to 25 km/h. Not ideal for flying—but exactly what my arpeggios needed.
Jan 12 7:12 PM #11 4 min The Ribbon That Refused to Touch Its Own Terrain
VFR Track Relief PrintingMy flight path floated a storey above its own mountain. GPS and terrain data have different opinions about ground.
Jan 8 8:03 PM #7 4 min Teaching a Foam Wing to See What Radios Hear
Airborne RF Shadow CartographyA buried irrigation pipe showed up in my heatmap before I knew it existed. The foam wing sees what I can't.