# Mechanical Keyboard Switch

How a red mechanical keyboard switch works, from the spring and stem to the moment its two contacts meet when a key is pressed\.

By B

Topic: Machines

[Open the interactive Jig](https://ask.jig.com/j/qUz1EX0115ez)

## Transcript

### 1. A tiny machine under every key

Under each key of a mechanical keyboard sits its own little switch\. This one is a classic design with a red stem\. Drag the key down, or drag the space around it to turn the view\.

The switch clips into a square hole just 14 millimetres across, smaller than a fingertip\.

### 2. The keycap and the stem

The keycap is just a cover\. Lift it off and you find the stem, a plastic slider with a plus\-shaped top\. The keycap clips onto that cross, so when you press the key, the stem moves straight down with it\.

### 3. Five main parts

Pulled apart, the switch has a bottom housing that holds two metal contacts, a coiled spring, the stem, and a top housing that snaps over everything\. The keycap sits on top\. Each part has one simple job\.

### 4. A peek inside

Here the front of the housing is cut away\. On the left stand two thin metal contacts\. The springy one, called a leaf, wants to touch the other one, but the stem's leg holds it back\.

The tips are gold\-plated so they keep conducting cleanly for years\.

### 5. Press the key

Press the button, or drag the key down yourself\. As the stem slides down, its leg moves out of the way\. The leaf springs across, the two contacts touch and electricity can flow\. That closed circuit is the key press\.

The contacts glow here only to show the moment they touch\.

### 6. Halfway is enough

The key can travel 4 millimetres, but the contacts meet after only 2\. That moment is called the actuation point\. Slide the key down slowly and watch for the glow\.

Typing lightly, without hitting the bottom, can be quieter and easier on your fingers\.

### 7. The spring brings it back

When you let go, the spring pushes the stem back up\. The leg slides back past the leaf and pushes it away from the other contact, so the switch is ready for the next press\.

A red switch needs about 45 grams of push to reach the actuation point, roughly the weight of nine sugar cubes\.

### 8. Three different feelings

Stem colours tell switch types apart\. Red is linear, smooth all the way down\. Brown is tactile, with a small bump you can feel\. Blue is clicky, with a part that snaps and makes a sound\.

### 9. Built for millions of presses

Each key has its own switch, so every press feels the same\. Switches like this one are rated for more than 100 million presses\. That is a press every second, day and night, for over three years\.

Many keyboards let you pull switches out and swap them for a different feel\.