Assembly plant vs manufacture plant

[johnbuckley]

Would someone like to hazard what was the difference between an assembly plant and a manufacturing plant? In Wilkins and Hill American Business Abroad (1964) it gives 1925 as the start date for both assembly and manufacture in Australia. And England 1911 for assembly with 1912 for manufacture. How many components had to bought-in or facbricated locally to make a foreign assembly plant a manufacturing plant?