Please note that the following tables are concerned with mounting fit. Owing to differing stem lengths within keycaps, keycaps from another switch family may not sit at the same height above the switch as the original keycaps. So long as the keycap can be pressed down a long way onto the slider, and it cannot be pulled off with too little effort, the keycap and switch are considered compatible.
Where compatibility depends on orientation, this is noted; otherwise, keycaps that fit, do so in both orientations.
|Futaba 1G complicated||Futaba 1G simplified||Alps SKCCAF||Sasse A||MEI||Cherry M5
|Futaba 1G simplified (Comptec)||No||No||Yes (very tight)||Yes||No||Yes (a bit loose)||Yes||No||Yes||No (too loose)||Yes||No||No|
|SMK 1G angled (Comptec)||Yes (very tight)||Yes (very tight)||Yes||Yes (90°/270° is loose fit)||No||No (too loose)||Yes||No||Yes||Yes||Loose fit||No||No|
|SMK 1G upright (SMK)||Yes||Yes||Yes||Yes||No||Yes (a bit loose)||Yes (a bit loose)||No||Yes||Loose fit||Yes||No||No|
|Cherry MX (Filco)||No||No||No||No||No||No||No||No||No||No||Yes (90°/270° only)||Yes (0°/180° only)||Yes (0°/180° only)|
|Cherry MX (GMK)||No||No||No||No||No||Yes (not fully)||No||No||No||No||Yes||Yes||Yes|
|Mitsumi hybrid (Commodore 64)||No||No||No (falls off)||No (falls off)||Yes||No (stem out of reach)||Yes||Yes||No (falls off)||No (falls off)||No (falls off)||No (stem out of reach)||No (falls off)|
|Tokai MM9-2 clone relegendable||Yes (0°/180° is loose fit)||Yes (90°/270° is too loose)||Yes||Yes (90°/270° is loose fit)||Yes (90°/270° only)||Yes (loose fit)||Yes (loose fit)||Yes||No (falls off)||No (falls off)||Yes (0°/180° falls off)||No||No|
- With Cherry MX switches, some keycaps (such as the MM9-2 clone flat low-profile relegendables) fit the slider correctly, but the hole in the shell is too small for the keycap stem.
- The MM9-2 clone keycaps are flat profile, but the mount is nonetheless orientated, with one cross axis wider than the other (only one orientation pair fits the MM9 series and its clones).
- Futaba simplified linear (1G): Acorn BBC Microcomputer, Wong’s (AWC) keyboard, with keycaps believed to be from Comptec
- SMK “vintage linear” (1G) upright: as above; these are a different fit to the genuine SMK keycaps included with the SMK-made BBC Micro keyboards
- Tokai MM9-2 clone relegendable: from AliExpress seller, so no hope of finding the source (switches are branded “G”, keycaps are unmarked)
Square post mounts
Often referred to as “RAFI mount”, this is a series of visually similar but not fully mutually compatible mounts.
|RAFI RS 74 M||Siemens STB 11||Siemens STB 21 2.5 mm||Sasse A|
|RAFI RS 74 M||Yes||Yes (a bit loose)||Yes (loose fit)||No|
|Sasse A (AliExpress)||No (too loose)||Yes (loose fit)||No (too loose)||Yes|
Unfortunately my collection of both switches and keycaps is very limited at present; I do not have RS 76 switches or keycaps, nor any Siemens keycaps. I also have no guarantee that the keycaps that came with my Sasse switches are original Sasse parts, although they are the correct design.