How Mechanical Keyboard Switches Work: Inside Every Keystroke

By MechKeyReview Team • Blog

Exploded view of a mechanical keyboard switch showing the four components: top housing, stem, spring and bottom housing

Every keystroke on a mechanical keyboard involves four pieces of plastic and one spring interacting in a sequence that takes about 40 milliseconds. Understanding that sequence changes how you evaluate switches — it turns abstract terms like "actuation force" and "tactile bump" into concrete, predictable sensations.

This guide explains the mechanics from the inside out: what each component does, what happens during a keypress, and exactly how linear, tactile, and clicky switches differ at the physical level.

The 4 Components of a Mechanical Switch

Every Cherry MX-compatible mechanical switch — regardless of brand or type — is built from the same four parts.

Top Housing
The upper shell that clips onto the bottom housing and guides the stem's vertical movement. It has a cylindrical cavity that the stem travels through. The material affects sound: polycarbonate (PC) top housings produce a softer, lower-pitched sound; nylon produces a higher-pitched click; POM gives a smooth, "silent" profile.
Stem
The moving part — the heart of the switch's feel. It slides up and down inside the housing. The stem's shape determines everything about how the switch feels: a stem with a smooth cylinder and straight legs = linear; legs with a pronounced bump = tactile; a leg profile that interacts with a click element = clicky. The cross-shaped post on top is where the keycap attaches.
Spring
A coil spring sitting inside the bottom housing, below the stem. It determines the switch's weight (actuation force). Heavier springs require more force to press; lighter springs need less. The spring also controls the return speed — how quickly the key rebounds after release. Factory springs can be swapped for aftermarket ones to change the weight profile of any switch.
Bottom Housing
The base that holds everything together. It contains two rails that the stem legs slide along (the most important lubing surface), a center post for the spring, metal electrical contacts at the bottom, and PCB mounting pins. The bottom housing material has the most influence on the overall acoustic character of the switch.

What Happens During a Keystroke

Here is the sequence, from start to finish, every time you press a key:

01 Resting state: the spring pushes the stem fully upward. The keycap sits at its maximum height.
02 Pre-travel: you begin pressing. The stem moves downward along the housing rails. The spring starts compressing. Nothing has been registered yet.
03 Actuation point: the stem has traveled a specific distance (typically 1.8–2.2mm) and the two metal contacts inside the bottom housing close. The electrical circuit completes and the keystroke is registered by the computer. This is the moment of input.
04 Post-travel: the stem continues downward until it hits the bottom of the housing (bottom-out). Total travel is typically 4mm.
05 Release: you lift your finger. The spring extends, pushing the stem back up. At a specific point (the reset point, slightly above the actuation point), the contacts separate and the key is ready to register again.

Key Specifications Explained

Switch specifications describe where in the travel these events happen. Here is what each measurement means.

SpecWhat it meansTypical value
Actuation ForceForce required to register a keystroke (at the actuation point)35–60g
Pre-travelDistance the stem travels before actuation1.8–2.2mm
Total TravelFull distance from rest to bottom-out4.0mm
Reset PointHow far the key must rise before it can register again~0.3mm above actuation
Tactile Force (tactile only)Peak force required at the bump — always higher than actuation force45–67g

Linear, Tactile and Clicky: How Each Works

The switch type is determined entirely by the shape of the stem and the presence of a click mechanism. The housing, spring, and actuation depth are nearly identical across types.

Linear, tactile and clicky mechanical switch stems side by side

3 switch types' stem profiles

Linear Switches

The simplest mechanism. The stem has straight legs that slide down the housing rails without any interruption. From the first millimeter to the last, the resistance is constant (increasing only as the spring compresses). There is no tactile feedback, no audible click — just smooth, consistent travel.

Examples: Cherry MX Red (45g), Gateron Yellow (35g), Gateron Black (60g), Kailh Speed Silver (40g). Linear switches are preferred for gaming (no bump = no hesitation) and by typists who prefer learning their own rhythm rather than relying on physical feedback.

Tactile Switches

The stem has two small legs with a pronounced bump shaped into them. As the stem travels down, those legs press against a corresponding bump inside the bottom housing. This momentary resistance — and then release — creates the tactile event: a physical indication that the actuation point is near.

The tactile bump occurs at or just before the actuation point, depending on switch design. After the bump, the stem continues smoothly to the bottom. Examples: Cherry MX Brown (45g actuation, 55g tactile), Gateron Brown, Boba U4 (silent tactile), Topre (electrostatic capacitive, different mechanism but tactile result).

Important nuance: Cherry MX Brown has a very subtle bump — many enthusiasts consider it barely perceptible. Switches like the Boba U4 or Holy Pandas have much stronger tactile events that are clearly defined.

Clicky Switches

Two main mechanisms exist. The Cherry mechanism uses a click jacket: a secondary plastic piece that surrounds part of the stem and clicks against the housing walls during travel, producing a sharp, high-pitched click at the moment of actuation.

The Kailh Box mechanism uses a click bar: a thin metal spring inside the housing that snaps sharply when the stem passes it. This produces a louder, crisper click and is considered mechanically more consistent than the jacket method.

Both mechanisms produce sound twice per key press: once going down (at actuation) and once coming back up (at reset). Examples: Cherry MX Blue (50g), Kailh Box White (45g), Kailh Box Navy (60g, heavy clicky).

Which Switch Type Should You Choose?

The answer depends on your primary use case and work environment, not personal mythology about which type is "better".

Use caseRecommended typeWhy
Competitive gamingLinearNo bump to interrupt fast, repeated actuations
Long-form typingTactileFeedback reduces fatigue over thousands of keystrokes
Open-plan officeSilent linear or silent tactileQuieter than membrane; won't disturb colleagues
ProgrammingTactile or linearPersonal preference; tactile helps with rhythm
Dedicated typist (at home)ClickyMaximum feedback; only if noise is not a concern

Frequently Asked Questions

The general architecture is standardized — housing, stem, spring, contacts — and the Cherry MX footprint is a de facto industry standard. But the internal geometry, material quality, and tolerances vary significantly. Gateron switches are often smoother out of the box than Cherry because of tighter tolerances. Kailh, Outemu, and Boba (Gazzew) each have proprietary designs with unique properties.

The actuation force — the weight required to register a keystroke. A 35g switch (like Gateron Yellow) feels very light; a 65g switch (like Cherry MX Black) requires noticeably more deliberate force. Heavier switches reduce accidental presses; lighter switches reduce finger fatigue over long sessions.

Yes, on hot-swap keyboards. Some users put heavy tactile switches on modifier keys and light linears on alphanumerics. This requires hot-swap sockets — soldered keyboards cannot be mixed without resoldering.

Silent switches have small dampening pads on the stem (usually foam or rubber) that cushion the contact between stem and housing at the top and bottom of travel. This absorbs the impact that produces the clacking sound. Gateron G Pro Silent, Cherry MX Silent Red, and Boba U4 are common examples.

Not sure which keyboard to buy after reading this? → Read our step-by-step buying guide

Want to improve your switches further? → How to lube mechanical switches

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