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This repair was not completed at a Repair Café or Fixit Clinic, but it was kind of interesting so I’m writing a post about it. Machining often involves arithmetic on very precise numbers. This is very tedious, so having a small calculator is very helpful. Being of a helpful nature, my school’s machine-shop has a…
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Part of my bicycle-lighting project involved crimping a splitter cable to split the output of the dynamo to the front and rear lamps. I used a DuPont connector for that because I had recently bought, after 4 years of consideration, a proper DuPont crimper. The input and output wires were 24 AWG solid wires with…
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Recently finding the need to bike home in the dark, and not wanting to regularly charge a battery-powered light, I decided to buy a used bicycle dynamo (for $40) to power a front and rear bike light. The dynamo is a bottom-bracket dynamo, which means it’s meant to be mounted on the bottom bracket (where…
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I recently bought a used cross-slide vise on craigslist for $35. It is a machinist’s vise mounted on two ways at right angles, with leadscrews controlling the vise’s movement along each way. It’s meant to be used on a drill press so holes can be located in the same manner as in a vertical milling…
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This event took place at the San Mateo Library. I mainly spent the 3 hours working on a broken IBM Selectric typewriter; I’ve had some experience restoring manual typewriters. The owner had taken it to a repair shop because the keys were a bit sticky, and it had come back broken. It appears the repairman…
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This Fixit Clinic occurred at the Maker Nexus in Sunnyvale. The first item was a Saeco Vienna Plus espresso machine. It automated the entire brewing process, including grinding and measuring the coffee, dispensing it into the “brew group” (the removable assembly where the actual brewing takes place), tamping it down, forcing water through the grounds,…
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Soldering iron tips are made of copper plated with a very thin layer of iron. Unfortunately, this plating can oxidize if you don’t clean and “tin” it (that is, coat it with solder to protect it), and this can be very annoying because the oxidation is difficult to get off and prevents the solder from…
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A spinning gyroscope can balance on a pivot, defying gravity by remaining horizontal while resting just on the tip of its axle. Instead of falling off the pivot, the gyroscope circles around it. The explanation for this amazing feat lies in the effects of precession. Like all other objects, the rotating wheel of the gyroscope…
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I made a gyroscope. Part of that involved casting 12 zinc weights to go around the rim of its rotor, which gave me a lot of practice ramming and pouring molds, and I learned a lot. Firstly, for my extremely rudimentary dirt-bonded sand, the right moisture level is just enough to turn the sand noticeably…
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This Repair Café took place at the Mountain View Senior Center from 11:00 AM to 3:00 PM. First, I worked on an Instant Pot® Vortex® Plus 10 Quart air fryer that wouldn’t power on; the owner said it had just stopped working one day with no major incident preceding it. After some light disassembly (prying…
