Introduction to keycaps for mechanical keyboards
The keycap is the material that covers the mechanical switch. These are typically made of plastic. Keycaps influence the typing experience, due to their shape, height, and acoustics.
Sculpted or uniform
“Sculpted” keycaps have varying degrees of height and angling, based
on where they are meant to be place on the keyboard. The idea is to
have the home row keys (where asdfghjkl are on a regular US Qwerty
layout) at a lower height than those below or above them to facilitate
finger movement and to make distant keys easier to reach.
By contrast, “uniform” designs do not differentiate between the different rows on the keyboard. These keys can still have angles, though they are all the same moving up/down from the home row. These keys are ideal for experimenting with different layouts, such as Dvorak or Colemak, as they do not impose where a key must be to feel right.
The shape of the cap
Keys come in all sorts of shapes and heights. There are short and tall ones. Some look more squared, others are circular. What one likes depends on how they are typing, the position of their chair and desk, et cetera.
The top of the cap (where we hit the key) has its own distinctive features as well: it can be flat, cylindrical, or sphrerical.
A cylindrical top has a deeper scoop through the middle than at the left and right sides. It is as if we had pressed the side of a cylinder against it.
The spherical top is deeper at the centre, with all four sides having a more noticeable edge or curve. Think of how it would be if we would press a sphere into the key.
The top of the cap is not merely stylistic. If you are used to sliding your fingers to reach keys, you will probably find the cylindrical design easier to work with. Though the sculpt will also be a factor.
As with most things when it comes to keyboards, one has to experiment.
Common profiles
| Name | Sculpted | Top | Height |
|---|---|---|---|
| Cherry | Yes | Cylindrical | Low-to-medium |
| OEM | Yes | Cylindrical | Medium |
| SA | Yes | Spherical | Tallest |
| DSA | No | Spherical | Low |
| XDA | No | Mostly Flat | Low-to-medium |
This is not exhaustive, though it provides the big picture. The sculpt differs from one profile to the other, as does the surface area at the top. There are many more profiles, many of which are variations of the above.
Suppliers may add their own spin to those profiles, such as OEM with a more spherical top or SA-like caps that are shorter than the originals.
The choice of material
The most common materials are types of plastic: ABS and PBT. Each has its own properties, with the former being more moldable than the latter. ABS plastic has more vivid colours combined with a smooth texture. Whereas PBT is sturdier and feels more coarse to the touch (which may be exactly what you prefer).
How high quality a cap is depends on the specifics of the production process and the thickness of the caps’ walls. Do not think that one kind of plastic is better than the other.
Acoustics
There are many factors that influence the acoustics of a mechanical keyboard: the materials of the board (metal or plastic), whether there are sound dampeners or other intermediate layers, the choice of key switch, and the properties of the underlying desk. When it comes to keycaps, the taller ones typically produce a deeper sound, while lower keycaps are more high-pitches. The thickness of the cap’s walls matters as well: a tall yet slim cap will sound hollow as opposed to a shorter but thicker one.
Where to start
If you are used to typing on a laptop that typically has uniformly shaped keys, then consider XDA as a first choice or a lower height sculpted profile like Cherry. Only go with very tall keycaps if you want to experiment with a more typewriter feel (and combine those with clicky switches for maximum effect).
Keep in mind that the profile of the key influences how you position yourself relative to the keyboard. Follow best ergonomic practices, so that (i) your palm and wrist are aligned and (ii) you are not typing at the keyboard from below. Arm rests and/or tilting and tenting the keyboard may be needed to get the right angle.