2020-10-19 4 min read


Notes, 2020-10-19.

One of the signifiers of personal maturity that I hold dear is the willingness to embrace mere acceptability. It’s also often hard for me; I like things that are both coherent and complete, and it feels neglectful to leave something in a state where it’s just good enough. Nevertheless, I believe that my life works best when it has some baseline level of failure and I try, in spite of myself, to maintain that.

(Ostensibly) Unrelated: Among other things, I’m working on updates to The Prepared’s Tool Guide. If you’ve got a tool that just *needs* to be tried out, send it here!

-Spencer Wright

The most clicked link from last week's issue (~12% of opens) was a quick hack to cleanly pour paint from a paint can. In the paid subscriber chat this week, a thread on reading/watching lists for C-level folks in hardware companies who don't have previous experience in hardware + many, many opinions on the optimal way to spread butter.

Planning & Strategy.

Making & Manufacturing.

  • A remarkable writeup of a truly wild and crazy computerized recumbent bike, built in the early 90s in (where else?) the Santa Cruz area. It involved “fiberglassing, sheet-metal fabrication, machining, FORTH software, system architectures, harsh-environment packaging, networking, bike tech, power management, embedded systems, audio processing, haptic interfaces, antenna design, and more” and had “about 160 corporate sponsors...along with over 45 volunteers who contributed their brilliance and skills. This was huge, looking back from a quarter century later; a mini-NASA emerged in the lab donated by Sun Microsystems — a dedicated team of geeks driven by the obsession of machines flickering to life, novel architectures, and the thrill of integrating the best available technologies into something that had never before been attempted.” This vehicle is insane, and includes among other things a Macintosh 68k, a 9600-baud modem, a “credit card verifier for on-the-road sales,” a Canon BubbleJet printer, and “an active head-cooling system with a 7-liter tank and a peristaltic pump to circulate ice water through the helmet liner.”
  • A good explainer on what kinds of tolerances are appropriate for CNC bent parts. Today, CNC press brakes predominantly use a technique called “air bending,” meaning that the final bend angle is determined not so much by the geometry of the die itself but by the depth to which the material is pressed into the die. The technique prioritizes flexibility, but small changes in material thickness result in wide variation in final bend angle. See also this comparison between air bending, coining, and bottoming.
  • Cable lacing is a traditional method of making neat cable harnesses with a continuous piece of linen cord.
  • A good video of the DJI Mavic drone factory.

Maintenance, Repair & Operations.

Distribution & Logistics.

Inspection, Testing & Analysis.

  • The homepage of the UCSD network telescope. They monitor roughly 1/256th of all IPv4 addresses, discarding all of the legitimate traffic and focusing on what’s left: “backscatter from randomly spoofed source denial-of-service attacks, the automated spread of Internet worms and viruses, scanning of address space by attackers or malware looking for vulnerable targets, and various misconfigurations (e.g. mistyping an IP address).”
  • A Bahtinov mask is a device that helps focus a telescope, and consists of a set of slitted grids that allow light to project a pattern through the telescope.


NASA's Workmanship standards, 195 pages of visual acceptance criteria for electronic & electrical components.

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