There are only a handful of keyboards
available that use them and most are dull,
utilitarian objects, the cheapest of which costs
well over £200. The main purveyor of them
is RealForce – a sub-brand of Topre – while
one of the most popular options is the Happy
Hacking KeyBoard (HHKB), which costs £260
and still uses a tiny 60 per cent form factor
with no numpad, cursor or function keys. You
can buy 60 per cent keyboards with more
popular mechanical switches for a quarter of
the price.
Spring forth
Finally, then, we come to what most people
imagine when they talk about mechanical
switches: those that use springs instead of
rubber domes. There are chiefly two types.
The first is called a buckling spring, which is
a much older style popularised by the IBM
Model M keyboards of the 1980s.
These switches rely on an internal spring
buckling under pressure from your finger, the
sideways movement of which tilts the metal
contacts together. In some ways, they’re
similar to rubber dome switches in that the
physical feedback of an initial pressure, then
a release as the spring gives way, is based
on the collapse of the spring-medium itself,
rather than a secondary system providing
that tactile feedback.
Much like with Topre switches, buckling
spring switches are a niche option, with the
only readily available keyboard to use them
being a clone of the IBM Model M made by a
company called Unicomp. It’s cheaper than
the Topre boards – just $104 US (approx
£76 inc VAT) for a full-sized keyboard, but
backlighting isn’t available, there are no
meaningful options for feedback type and
there are relatively few keycap options.The Cherry on the cake
All of which brings us to the single most
popular and recognisable incarnation of the
mechanical keyboard switch: the Cherry MX.These switches – and the main copycats
and clone versions available – incorporate
several key features that make them so
enduringly popular.
The most fundamental advantage of the
Cherry MX switch design is that the spring
action and feedback are decoupled. In
these switches, the spring simply provides
tension, with the tactile bump feedback and
clacking noise (that’s inherent to switches
with a buckling spring) provided by separate
components within the switch. Similarly, the
contact actuation isn’t caused by the spring
but by other components.
Specifically, inside the outer housing of
each switch is a plastic plunger that connects
to the keycap, and under the plunger is the
spring that provides the tension. A small
sloping plastic piece on the side of the
plunger pushes against a metal contact in
the housing of the switch. In its ‘up’ positionthe plastic piece keeps the metal contact
open, but when pressed, the contact can slide
down the plastic slope until it touches the
other contact.
In its simplest form, this switch provides
what’s called linear feedback, with the switch
and its metal contact smoothly gliding up
and down. The only feedback to tell you that
you’ve pressed the key is the action appearing
on the screen, or the key bottoming out.
However, in other switch designs, the little
plastic slop on the plunger can incorporate
a bump that initially makes it a little harder
to press the switch until the bump has been
passed. This slight tension and release
provides some tactile feedback to the
user. These are, funnily enough, known as
tactile switches.
The third of the most popular variants
has a similar bumped slope as the tactile
switch. However, here the bump is formed
on a completely separate piece of plastic
that floats freely around the main shaft of the
plunger. When pressed, the plunger pushes
down on the floating section until the bump
is passed, at which point the floating piece
snaps downwards from the force of the
sprung metal contact. This creates a very
noticeable tactile and audible feedback that
gives this type of switch its name: clicky.
The main advantage of this design is that
the separation of components means you can
tweak each aspect of the switch individually.
You can opt for stiffer or lighter springs,
differently profiled bumps or add other
components such as rubber dampeners,
where one change won’t affect the operation
of the other.
More recently we’ve also seen companies
offer switches where the actual switch
detection is performed electromagnetically,
or by breaking a beam of light. Technically,THE SPRING SIMPLY PROVIDES TENSION, WITH THE TACTILE BUMP
FEEDBACK AND CLACKING NOISE PROVIDED BY SEPARATE
COMPONENTS WITHIN THE SWITCHCherry alone makes dozens of variants of its MX switch design, with different combinations
indicated by the colour of the stem
Kailh’s Box switches are one of the popular
alternatives to straight Cherry MX clonesalternativesrna to straight Cherry MX clonesMX cl neesFEATURE / DEEP DIVE