Manufacturing details of switches are not widely known. Some details are disclosed in patents, but many others remain a mystery. Switch production was initially manual to some extent. Meryl Miller provided a photograph of a factory worker assembling a Datanetics DC-50 switch using a special jig, although the switch elements (the metal–mylar sandwich) are reported to have been automatically fabricated.
In 1974, Oak Industries placed an advertisement in Electronics in which they mentioned what they considered to be “the most sophisticated fully-automated keyboard switch assembly facility in the industry”. The advertisment covered Series 400, 415 and 475 and did not state whether this automated production line covered all their series, or just one or two of them.
Some Tai-Hao APC Series switches have a reversible base, that can be attached in the 0° and 180° orientations. The reason for this design, they reported, was to permit automated assembly of the switches. As APC Series was introduced around the start of the 1990s, it would seem that automated assembly reached Taiwan fairly late, as the reversible base appears to have been a later modification and one that would later be removed.