https://www.nytimes.com/2019/01/28/technology/iphones-apple-china-made.html
A Tiny Screw Shows Why iPhones Won’t Be ‘Assembled in U.S.A.’
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In China, Apple relied on factories that can produce vast quantities of custom screws on short notice.
In Texas, where they say everything is bigger, it turned out the screw suppliers were not.
Tests of new versions of the computer were hamstrung because a 20-employee machine shop that
Apple’s manufacturing contractor was relying on could produce at most 1,000 screws a day.
The screw shortage was one of several problems that postponed sales of the computer for months,
the people who worked on the project said.
By the time the computer was ready for mass production, Apple had ordered screws from China.
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