This section documents keycap mount forms, dimensions and compatibility between brands.
A number of switch series were customised by the manufacturer to accept different keycaps, including keycaps from rival manufacturers. Known instances of this are detailed below.
|Alps SKCC||General Instrument Series S950 is a variant of Alps SKCC series that takes Clare/Pendar keycaps. Looking at the injection mould cavity numbers, either Alps provided the tooling (or the plans for the tooling) or produced these switches on GI’s behalf.|
|“Side-angled” cream shares a keystem customisation with SKFF; in both cases, these switches are thus far only known from Facit typewriters from Sweden.|
|Alps SKFF||These share the same apparent keystem modification as SKCC above.|
|Cherry M7||M51-0131 is a variant of Cherry gold crosspoint with a custom mount. The reason for the custom mount remains a mystery. M51-0131 is a replacement part number for M51-0129, and one assumes that the previous version of the switch had the same custom mount.|
|Cherry M7 Style D itself is a mystery. So far, it has only been found in SAGEM keyboards. These switches are Clare/Pendar mount, which suggests that they were a custom part made for Sagem to permit them to use existing Belgian or French-made keycaps.|
|Cherry M9||Cherry M1 (or M11) is a ground-up redesign of Cherry M9 created as a drop-in replacement to Datanetics DC-60.|
|Cherry M94A-1GBR is an M9 variant that takes the same keycaps as M51-0131; these are found at various sources in Bulgaria (both used and NOS).|
|Cherry M9 in general was widely used in typewriters, using at least one custom mount, marked “TA” in the M9 part number schema. M94A-18NI is another “TA” type, although it will accept Cherry MX keycaps.|
|Datanetics DC-50||Meryl Miller rediscovered a single DC-50 switch—with no part number—that was part of a custom order for NCR of switches with a bar mount.|
|Datanetics DC-60||Evidence suggests that DC-60 was customised to accept MX keycaps (the cream DC-60 type); this has been found in the same keyboard as Cherry M1, where the latter was used for space, but with the standard DC-60 mount.|
|Micro Switch SD||Plunger type C was a custom type for NCR. This is a bar mount, whose dimensions differ somewhat from the custom DC-50 switch made for NCR. It looks like it is the same stem as that of the illuminated switches with plunger-integrated LED, as though NCR only wanted a single keystem for all|
|Plunger type K is another custom type. This has been found in a Bunker Ramo keyboard. There is no indication that this was customised specifically for Bunker Ramo, but it is definitely a non-standard mount.|