Mechanical keyboard switches, from scratch

A mechanical switch is the small plastic-and-spring assembly under each keycap. There's a switch under every key on a 'mechanical' keyboard, and the entire feel of the keyboard — the smoothness, the bump, the click, the sound — comes from which switches are in it. Switches are also the most upgradable component on a keyboard: most modern boards let you swap them.

Anatomy of a switch

Every Cherry MX-style mechanical switch has the same six parts: top housing, bottom housing, stem, spring, two metal contact leaves, and (sometimes) a click jacket or bar. Pressing the keycap pushes the stem down through the housing, the stem displaces or interacts with the leaves, and at some point the electrical circuit closes — that's the actuation. Releasing the key lets the spring push the stem back up.

Stem — the part that moves; its shape determines whether the switch is linear, tactile, or clicky.
Spring — controls how heavy the key feels. Spring weight is rated in grams of force at bottom-out.
Housing — top and bottom shells. Material (PC, nylon, POM) influences sound and slight smoothness differences.
Leaves — the metal contacts inside the bottom housing that close when actuated.

The three categories

Linear switches

Smooth top-to-bottom travel with no bump or click. The stem slides past the leaves and closes them silently. Linear switches feel like pressing a smooth button — fast, predictable, no tactile feedback.

Best for fast typing and gaming where you don't bottom out — the smoothness rewards floating press technique.
Often described with sound words: 'creamy', 'thocky', 'poppy'. The bottom-out sound is the dominant character.
Examples: Cherry MX Red (light, scratchy), Gateron Yellow Pro (smoother, popular budget choice), Gateron Oil King (creamy, factory-lubed), Cherry MX Speed Silver (short throw), Razer Linear Optical, Holy Pandas... wait, that's tactile.

Tactile switches

A bump on the stem creates a small resistance partway through the travel. You feel the bump, the switch actuates around the same time, and then the rest of the travel is smooth. The bump is feedback — you know the key registered without having to bottom out.

Best for typing-heavy use. The bump gives you a stop you can ride to avoid bottom-out.
Bump position varies: 'early' bumps near the top, 'late' bumps closer to the bottom. Most beloved enthusiast switches (Boba U4T, Holy Panda, Glorious Panda) have a strong early-mid bump.
Examples: Cherry MX Brown (mild, controversial 'fake tactile'), Gateron Brown Pro, Boba U4T (deep, thocky), Holy Panda (sharp tactile, loud), Topre (capacitive rubber dome — separate technology with a distinctive deep tactile feel).

Clicky switches

A tactile bump plus an audible click. The click comes from either a click jacket (a separate sleeve that snaps over the stem) or a click bar (a piece of metal that flicks against the housing).

Loud, satisfying, and divisive. Great in a private office; terrible on a Zoom call or in a shared room.
Click jackets (Cherry MX Blue, MX Green) have a softer 'tick' on press and a quieter release.
Click bars (Kailh Box White, Box Jade, Box Navy) produce a sharper, louder click on both press and release.
Examples: Cherry MX Blue (mild), Cherry MX Green (heavier), Kailh Box White (sharp, popular), Kailh Box Jade (heavier crisp click).

Spring weight

Spring weight is the force needed to fully press the switch. Switches typically list two numbers: actuation force (force at the point the switch registers, around 2 mm) and bottom-out force (force at the end of travel, around 4 mm). Some switches list only one or the other.

Bottom-out force	Feel	Typical use
35–45 g	Very light, can cause typos for heavy hands	Speed typing, finger-only gaming
45–55 g	Medium-light, the most common range	All-purpose typing, gaming
55–65 g	Medium, classic Cherry territory	Default for most enthusiast linear switches
65–75 g	Heavier, more deliberate	Typing-focused users, reduces accidental presses
75 g+	Very heavy	Niche; some Topre and clicky variants only

Tip

Spring weight is the easiest switch property to change — a spring swap takes about 30 seconds per switch with the right tools. If you like a switch but want it heavier or lighter, swap the spring rather than the whole switch.

Pre-travel, total travel, and actuation

Pre-travel (actuation distance): How far the key travels before the switch registers. Standard MX switches actuate at 2.0 mm. 'Speed' switches actuate sooner (Cherry MX Speed Silver at 1.2 mm, Kailh Box Speed at 1.0 mm).
Total travel: Total downward distance the key can move. Standard is 4.0 mm. Low-profile switches use 3.0–3.5 mm; some optical switches offer adjustable actuation (Wooting Lekker, Razer Analog) — you choose the trigger depth in software.
Reset point: Distance going back up at which the switch deregisters. Lower reset point = faster repeat presses. Hysteresis is the gap between actuation and reset — bigger gap means more keystroke 'chatter' immunity, smaller means faster repeats.

What lube and films actually do

Two of the most discussed switch mods in the hobby:

Lube: A thin layer of grease (Krytox 205g0 is the canonical choice) applied to the inside of the switch housing, the spring, and the stem rails. Reduces friction, eliminates spring ping, smooths the press. Pre-lubed switches (most modern enthusiast switches) do this at the factory; hand-lubing is the original DIY mod and still slightly improves most switches.
Films: Thin gaskets placed between the top and bottom housing. Take up slack from manufacturing tolerances, making the press feel slightly deeper and the sound slightly cleaner. The improvement is small but real.

Note

Pre-lubed and pre-filmed enthusiast switches (Akko, Gateron Oil King, Cherry MX Black Hyperglide, etc.) have closed most of the gap with hand-modded older switches. You can get an excellent keyboard with no aftermarket mods today.

Optical and magnetic switches

Optical: Uses a light beam to detect actuation instead of a metal contact. No debounce window needed — slightly faster, no metal wear. Examples: Razer Optical, Gateron Lekker (Wooting), Glorious LK Optical.
Hall-effect / magnetic: Uses a magnet on the stem and a Hall-effect sensor on the PCB to measure travel continuously. Lets you set actuation depth in software (e.g., 0.1–4.0 mm), enable rapid trigger (the key resets the moment you start releasing), and use the key as an analog input (Wooting analog WASD, racing pedal-style throttle). The biggest gameplay-relevant innovation in years.

How to pick your first switch

Buy a switch tester ($10–20 with 9–12 switches). Press each, gently, multiple times. Note which feel best.
Decide linear / tactile / clicky based on environment (shared room? clicky is out) and use case (typing-heavy? lean tactile).
Pick a weight in the 45–60g range as a beginner. Too light invites typos; too heavy fatigues.
If you can, buy a board with hot-swap sockets so your first switch isn't your last. Switching later costs $30–60, not a new keyboard.