KBK update for Saturday, 14th August

I could not decide whether Micro Switch’s 63SC31-1 engineering prototype was the full-height Micro Switch SC or the DIN-compliant version. Further examination would suggest that it is the DIN-compliant version, the SC/CT/ST design that everyone knows. The use of cylindrical keycaps is a good indication, as is the distance of the keycaps from the mounting plate.

Although the full-height switches appear in advertisements and are available for sale on eBay, it seemed like no full-height keyboards had ever been found. It turns out that they have: some Symbolics 364000 keyboards use them. Keymacs’ 364000 is linear, while item 114933868710 on eBay is for a tactile example. (That listing uses my graph for SD Series tactile, while the switches seem more likely to be SC Series, although either type is possible.)

These examples also explain eBay listing 111097281580, for a single SC10075 actuator: despite the strange shape of the plunger, this really is standard Micro Switch mount, but classic SC plungers have corners removed, perhaps to save on plastic.

(No links to the eBay pages as they will only become 404s in time.)

I also never realised the significance between the blue and black plungers on ST switches until now. All the examples with blue plungers take keycaps with a blade stem inside, while those with black plungers take regular Honeywell-mount keycaps. Both types were widely used, and the reason for this remains a mystery.

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