mikewarot 19 hours ago

Having made an 4 year excursion from IT into the world of making gears, I can attest that what seems like something fairly simple from the outside really isn't.

Just like a bearing, gears (ideally) have a rolling contact. The smoother and harder the faces the better, until you get to the point where fractures and spalling occur. The best gears are cut, sent out to be hardened via heat treat, then ground (with "superfinishing") to exact size. As with bearings, you have to get the size just right for long life.

  • nom 6 hours ago

    Making featureless metal balls seems very easy, they have only one dimension and are perfectly symmetric.

    .. until you realize that:

    - they have extremely tight tolerances - they function together, a single defect one ruins the whole assembly - you have to make millions of them for cheap

    Some things are deceptively hard. For a related fun fact, check out China's ballpoint pen adventures.

    • Cumpiler69 6 hours ago

      >China's ballpoint pen adventures

      True. Though they've moved up in the world since then. They now have their own semiconductor fabs. Chinese industry of today is way more advanced than the China of the 90's making low margin nick-nacks.

      • binary132 2 hours ago

        go ahead then, explain their high-speed rail issues…

rabiescow an hour ago

Thanks for sharing, reddit is wild how many great and randomly extremely thoughtful responses there are there!

It's often easy to forget among all the noise but reddit has a lot of the best of internet too!

usrusr 19 hours ago

Setting away Mosquitos (the real Wunderwaffe of that war) for freight runs (and for stuffing the occasional Nobel Price physicist in the bomb bay) tells a rather different story about the importance of swedish-made ball bearings for UK arms production:

https://news.ycombinator.com/item?id=37884749

  • pomian 18 hours ago

    Great article about the Mosquito! Thanks. That's yet another HN rabbit hole! It confirmed a friend's war story I heard, first hand - about escaping from a German POW camp near Berlin - then proceeding to Copenhagen, with the help of the Danish underground, stealing a rowboat from a German yacht, rowing to Sweden at night. The wounded one stayed in Malmo, the other two continue to Stockholm. There they went to they Polish embassy. One stayed there, the other was sent to Scotland that night in a mosquito. (Later he went to London, then dropped by parachute behind enemy lines.) Now it's the first time I read a story to verify that other first hand account! (I obviously summarized an amazing tale.)

emmelaich 17 hours ago

Similar dynamic to YKK's dominance of the zipper industry.

Now challenged by a few look-alike Chinese companies.