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Basic keyboard terminology

!!! UNDER CONSTRUCTION !!!

This is a collection of the most common keyboard related terms. After reading this you will be able to comprehend what's going on in the community (r/mk, r/emkb, geekhack, deskthority etc.).

Being familiar with the basic vocabulary is crucial both for buying parts and the actual process of keyboard customization and building.

This is general stuff for beginners. There is a more comprehensive keyboard lexicon with more advanced terms. Also, there is a learning plan to gradually initiate you into building true custom keyboards, creating custom logical layouts and reaching your endgame.

Endgame is the Holy Grail of keyboard enthusiasts. Your ultimate setup. Ofc there's no such thing. Once you buy/build oneit there are new switches and keysets to try.

Rubberdome vs mechanical keyboards

The cheap keyboards still found in most offices are almost exclusively rubberdomes. They have a rubber sheet under the keys helping register keypresses and pushing back keys when released.

Rubberdomes are cheap and ideal for mass production but they are hard to customize or fix if broken. People usually buy a new one when a key or the rubber is damaged. They are generally considered inferior to mechanical keyboards.

Mechanical keyboards have little mechanical switches under each keycap. They are much more expensive than rubberdome ones. Their strenght lies in customization. Switches and keycaps can be replaced. Mechanical keyboards are often easily programmable.

Parts of a keyboard

Keycaps, keyswitches, plate, PCB, controller, case, cable. pic

Notable areas of a keyboard

Numpad, F-row, number row, navigation cluster, alphas, modifiers.

Form factors & physical layout

The normal fullsize keyboard is considered 100%. Stripping the number pad results in a 80% or tenkeyless (TKL) form factor. You get a 75% with turning the navigation cluster into an upright column of keys while retaining arrows.

The popular 60% form factor is characterized by the lack of numpad, navigation cluster, arrows and F-row. 40% keyboards don't have the number row either, while 30% ones have almost exclusively the alphas + some modifiers to access layers.

More on form factors.

Split keyboards

Split keyboards are considered more ergonomic (see ulnar deviation). Both true separate and fixed-angle monoblock keyboards are called split.

True splits are e.g. Corne, Iris, Kyria. You can place the two halves as you like.

Monoblocks are Atreus, Kynesis Advantage etc. The split angle is fixed, but the overall, the keyboard is easier to pack up and travel with.

But there are literally hundreds of split designs. See my collection of splits.

Staggering

Classic staggering, ortho/ortholinear boards and columnar staggering. The horizontal shift in the placement of keys on a classic board is called staggering. It was necessary for mechanical typewriters but is obsolate now.

Accidentally, the classic staggering turned out useful for the right hand (see ulnar deviation) but is a disaster for the left hand.

Ortholinear boards have their keys in a regular grid. This looks cool and clean but is only considered ergonomic if split (see ulnar deviation).

Columnar stagger is when the keys are vertically shifted according to your fingers' natural direction of movement. Most splits designed with ergonomy in mind are more or less columnarly staggered.

Keycaps

Keycaps are the little plastic parts on the switches your fingers actually touch.

Replacing keycaps is probably the easiest way of customization. You need a keycap puller (or a piece of insulated wire to protect the edges) and can remove your caps.

If you want to change your keycaps, compatibility is key. Most keysets are MX compatible (+ shaped stem), but low profile Chocs need different caps. Before placing an order make sure what type of switches you have.

Keycap profiles

There are different keycap profiles with different shape and height.

Common keycap profiles are OEM, Cherry, SA, DSA and XDA. Newer profiles are MDA, MT3, KAT, KAM etc. Low profile keycaps are e.g. Kailh Chocs (not MX compatible).

Keycap profiles can be characterized be properties like sculpted/uniform, spherical/cilindrical, high/medium/low profile etc.

A uniform keycap profile has identic keys in all rows (DSA, XDA, Choc). They are compatible with alternative layouts (Dvorak, Colemak) since you can put any cap in any row. Sculpted keycaps have differently shaped caps in each row (SA, Cherry, MDA etc.). This may help typing confortably but makes keycap compatibility on exotic layouts harder.

The cutout on top of a spherical (SA, DSA, MDA) keycap is shaped like a sphere, while that of cylindrical ones (OEM, Cherry) is like.. well.. a cylinder.

Most keycaps are high profile but there are low profile ones (Choc). Too high caps (SA) can wobble. They look cool and classic but may not be the perfect profile for typing.

Homing keys are the two keys (usually F and J) of the home row where your index fingers rest. There are different approaches for marking these: deep dish (SA) is a slightly deeper top. Other profiles have a small dot or dash on these two caps (homing bump).

Home row btw is the middle row (asdf...) and home positions are asdf-jkl;. At least until you start to customize your layout.

Keycap legends

Legends on cheaper keycaps are usually dye-sublimated.

Double shot keycaps are more expensive. Two differently colored plastic materials are injected into molds in two turns. Doubleshot is considered more durable but this only makes a difference if you use the same set for decades.

Laser etching is another way of marking keycaps.

Blank caps come without legends. They are for touch typers (which should be you top priority if you .

Keycap group buys and drops

Manufacturers only produce a new keyset if there's enough demand. Designers run interest checks [IC] and organize group buys [GB] where people buy stuff in advance, prior to production. Actually, you buy the idea. If the MOQ (minimal order quantity) is met, the set is produced. However, you may wait months for it to arrive.

Grab bags

Keycap manufacturers sell incomplete sets, scraps etc. in grab bags. People buy this random trash. Sometimes you may have luck though. "It's just a fun way of buying trash and maybe getting some cool keycaps." (biosh4ck)

Keycap manufacturers

SA was originally made by Signature Plastics. Maxkeys bought their old molds and started to produce SAs too.

GMK is a well-known German manufacturer of doubleshot (and pricy) caps with Cherry profile.

You can find MT3 keycaps on Drop.

Artisans are rather artworks than keycaps but still belong to this topic. They are pricy and are usually sold in limited numbers or raffles.

Keyswitches

Basic switch types are identified by stem color. The most common types of keyswitches are linear (red), tactile (brown) and clicky (blue).

This is the inner structure of a key: pic Top and bottom housing, stem, spring, leaf, click bar.

Linear switches (originally red or black) are silent. They don't have a bump on the stem or a clickbar so the movement and feel is gradual. They are ideal for gamers or in an office environment where you don't want to annoy your coworkers with clicking.

Tactile switches (originally brown) have a small bump on their stem. This gives a little tactily feedback when typing and can help typers. Feeling the tactile bump you can stop pressing the key before hitting the switch housing (bottom out).

Clicky switches (originally blue) are tactile too. Additionally, they have a clicking mechanism (click jacket or click bar) to produce the characteristic sound. This may be not the best solution in an office environment.

Since most brick and mortar shops have gaming keyboards you can try the feel of these basic types.

General rule:

  • If you're a gamer, you most likely need linear switches.
  • If you have people around you (at home or at work) linears or silent tactiles can work best.
  • If you are mostly alone in your room feel free to enjoy the sound of clickies.
  • Replacing switches is made easy by hotswapping. This means they are not soldered and you can pull them out and insert new ones. This is only possible on hotswappable boards where there are hotswap sockets on the PCB.

    However, this may make the keyboard more vulnerable. Be careful not to lift a soldering pad when changing switches.

    Switch properties

    There are some common terms describing and characterise switches and a keypress in general. Manufacturers, vendors and reviewers characterize a switch by these common parameters.

    Bottoming out is to press the key fully, until the keycap hits the bottom housing.

    Total travel distance is the distance to bottom out. Generally 3.5-3.6 mm, but less at speed switches or low profile switches.

    Total travel can be reduced by adding an O-ring to the cap. O-rings are simple silicon rings.

    Activation/Actuation point is the distance to the point the keypress is registered. This can be much less than total travel, eg. 1.1 mm on speed switches.

    Activation/Actuation force is the force needed at that point.

    Tactile point/force. The distance and force to get to the tactile bump on tactile and clicky switches.

    Switch weight. Based on the actuation or tactile force switches can be classified as light or heavy. A 40gf switch is at the light end of the spectrum while a 80cN one is rather heavy.

    Lubing. Switches can be lubed. Some people like the feel that way better.

    Force curves show the characteristics of switches and force needed for a specific travel distance. More on reading a force curve.

    Force values are expressed in gf (gram-force) or cN (centi-Newton). Although these are different they can be considered pretty much equivalent.

    Mounting switches

    Switches come in two forms: 3-pin versions are called plate mount and 5-pin versions PCB mount. The two smaller plastic legs of a PCB mount switch can be cut off if it interferes with anything.

    Keyswitch manufacturers

    Cherry was the first big name creating Cherry MX switches. Their patent expired and Chinese companies started to copy them. Gateron, Kailh, Outemu are some manufacturers. These newer companies not just copy but also innovate. Some of their switches are actually better than the original.

    Keyboard accessories

    If you have still money to burn there are custom cables with detachable (aviator) connectors, wrist rests, deskmats, artisans etc.

    Logical layout

    As we've seen, the physical layout is defined mostly by form factor, splitness and staggering.

    Logical layout is the mapping of characters and functions to the physical keys. Programmable keyboards store this keymap on the controller and this can (and should) be customized too.

    Common logical layouts / alternative layouts

    The most common logical layout is QWERTY. This is very old and obsolate.

    Other popular alternatives are Dvorak, Colemak, Workman etc. These try to put the most frequent letters on the home row.

    However, with programmable keyboards you can customize the position of each character according to your typing habits.

    This customization is called logical layer optimization and can be achieved intuitively, based on key frequencies and heatmaps or with more sophisticated methods like genetic programming.

    Ways of building

    As you've seen there are many different keyboards just like there are various ways to build a keyboard. That's why you won't find a general build guide.

    Nevertheless, build logs are very useful for learning. They document building a specific keyboard.

    The controller is the brain of your keyboard. It sits on a PCB (printed circuit board) and runs the firmware flashed on it. The PCB connects electronic components (switches, diodes and LEDs) with traces.

    A PCB spares you some work but you can go with handwiring too. Handwiring is cheaper but tedious.

    But this is advanced stuff.

    After absorbing the info above you are ready to build something simple like a macropad.