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> Can confirm: there are about two dozen bottom bracket tools in the drawer. In fairness, bottom brackets have been a pain in the ass for decades. Even on old ones, there are a couple different hook spanners and pin spanners you might need for the lock ring and adjustable cup and a couple other weird-ass wrenches that you need from time to time. Shit's usually tight AF too, and the various tools that were fine for manufacturing a bike get a little iffy when everything's good and seized after 20 years of neglect.

I agree the various (totally random) BB standards are a pain; every bike build I've done has meant that I CADed and then 3D printed the tool (100% infill PETG, takes ~2 hours on a Prusa MK3S).

Curious how long it is before we get 3D printing tech easy enough to where shops can have a printer, download any special tools for a bike assembly, and make them in a few hours.

Hope is a great example of a manufacturer who does this today: https://www.hopetech.com/open-source-tools/


No, it's still illegal


Location: Austin, TX

Remote: Yes, open to hybrid or in person

Willing to relocate: Yes (SF, Seattle, Denver/Boulder)

Technologies: Product leader, platform builder, API enthusiast, AI, Cloud, IaaS/PaaS

Résumé/CV: linkedin.com/in/asciimike

Email: hn at mikemcdonald dot co

Experienced product manager looking for a group PM/director role in AI infrastructure, platforms, or tooling. I build platforms that developers love, historically at Firebase, Google, GitHub, and most recently, Crusoe, where I built a GPU IaaS platform that powers many quickly growing AI startups and an increasing number of enterprises.


Possibly a dumb question, but why can't we grow synthetic quartz in the same way we grow silicon wafers? Or can we and it's just not cost effective vs mining?


We can but synthetic quartz faces the same problem as hydrocarbon fuels: we can make synthetic natural gas if we use enough energy, or we could exploit the geological processes that created it over millions of years and extract it.

High-purity quartz from areas like Spruce Pine typically forms in pegmatites, where slow cooling of magma allows large, defect-free crystals to form. Hydrothermal fluids permeate these rocks while they’re cooling, effectively leaching out impurities. If the geochemistry is just right, over millions of years, this process repeats several times creating very high purity quartz deposits that are very difficult to replicate in laboratory conditions.


Any idea how big these quartz crystals needs to be?

Single crystal sapphires ~250kg are grown in production, so it should be possible with reasonable effort to do similar for quartz:

https://en.wikipedia.org/wiki/Kyropoulos_method

---

Seems like it already is: https://en.wikipedia.org/wiki/Quartz#Synthetic_and_artificia...

No mention there of purity though.


The https://en.wikipedia.org/wiki/Czochralski_method is the actual big crystal growing process, to which this quartz is just the input. Effectively we repeatedly make a crystal with the impurities moved to the end, then saw off the end and discard it, then re-melt the crystal to make it even purer.


It’s not the size that’s hard but the 99.9999% purity. The quartz from these mines is crushed, sorted for impurities, and fused/annealed into larger crystals before they’re ready for the semiconductor industry.


The single crystals of silicon that are made are cylinders with a diameter of 0.3 meter and a height probably of around 2 meter or even more.

The crucible must be bigger than that. The crucible is made from fused quartz glass. So the mine does not need to have big quartz crystals. They must be only pure. The mined crystals are melted together and processed like any glass, except that processing quartz glass is difficult, due to the very high melting point and the high viscosity of the melted quartz.

The melting of the pure quartz requires itself a crucible made from materials that resist to even higher temperatures, e.g. a crucible of molybdenum or even a crucible of iridium, for the lowest contamination with impurities.


Well that's not nearly as neat looking as I naively expected a large sapphire to look like.

I suppose the usual gem color arises from the impurities?


They seem pretty ugly if they're not cut. ;)

https://www.youtube.com/watch?v=-INytU_pdkg


Can nanoassembly produce quartz more efficiently?

/? nanoassembly of quartz https://www.google.com/search?q=nanoassembly%20of%20quartz mentions hydrothermal synthesis,

Which other natural processes affect the formation of quartz and gold?

From https://news.ycombinator.com/item?id=41437036#41442489 :

> "Gold nugget formation from earthquake-induced piezoelectricity in quartz" (2024) https://www.nature.com/articles/s41561-024-01514-1 [...]

> Are there phononic excitations from earthquake-induced piezoelectric and pyroelectric effects?

> Do (surface) plasmon polaritons SPhP affect the interactions between quartz and gold, given heat and vibration as from an earthquake?

> "Extreme light confinement and control in low-symmetry phonon-polaritonic crystals" like quartz https://arxiv.org/html/2312.06805v2


We can, using big autoclaves and a process called hydrothermal synthesis. It's how we make single crystals that get sliced and diced into quartz oscillators. But the process takes a long time, think mm/day, and isn't really appropriate for making big things like crucibles.


Cunningham's Law: "the best way to get the right answer on the Internet is not to ask a question, it's to post the wrong answer"


Where/how did you learn welding? Have been considering doing a community college welding course (as they have all the equipment, instruction, etc.).


MIG is really just a glue gun for metal. For things where structural integrity isn’t critical you MIG stuff together by watching a couple YouTube videos and then going at it.


(note that of course mig can be great for structural things, it's just easy to get started)


What I appreciated about metal shop class is the casual (software-like?) attitude towards toolmaking. Would that step go better with a jig? Weld one up on your workbench, and then angle grind everything off when you move to the next phase...


I was using my dad's shop and MIG welder, so he was able to give me an intro. A buddy of mine is a millwright and came over and kindly taught me some tricks which brought me welds up to an acceptable quality.

After learning, I'd have to agree with one of the other responses, learning by Youtube is probably feasible. It's safer than I expected (less concern about touching metal in the ground path) though I'd strongly recommend investing in quality gloves, a quality helmet, and good thick pants, and a long-sleeved shirt / overcoat.

I thought about taking a course but I found this way of learning a lot more fun and engaging (if you're fortunate, as I am, to have experienced people in your life).


Bear in mind that some metals can be toxic when welded.

ie galvanised stuff generates gaseous tin or zinc (~white smoke, i don't remember which). Bad in a confined space like a shed or garage.

So there are some non-obvious considerations that Youtube video's don't seem to mention. :(


you can get cheap welders and use flux core so you don't even need gas shielding.

something like this works well.

https://a.co/d/8XMYx7j

for thin steel or aluminum you really do need shielding gas.

https://youtu.be/X4WkDDnvS7g


Here's that first link but without the tracking linking you to everyone who clicks on it (and vice versa):

https://www.amazon.com/dp/B0B6HL28ZP


I'm scared to ask, but how big is said CPU (and how many kW is it putting out)?


TBD, most likely a 4-bit ALU, but it will boot linux via emulation :D


I'd love to bring a Japanese beverage vending machine and drop it off in the middle of a reasonably populated US city and see how quickly it gets used (or, unfortunately, destroyed). Would only accept Yen (and ideally Suica/Pasmo, though unsure if those would work properly?).


Where do you source vintage audio gear from?


ebay and other local sources, but mostly ebay and patience, for the buyer protection.


Mind sharing the resource material? I've looked into this briefly, seems like a common-ish path for flat bed trucks is using a surplus S-280 (e.g. https://www.ramims.com/products/S-280C-G).

I really like both:

- https://www.dirttrailswanted.com/overland-peanut (S-280 route)

- https://wabisabioverland.com/ (custom build, both in house and contracted through: https://totalcomposites.com/)


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