# Cigarette Lighter Assembly

Build a pocket lighter part by part and see how fuel, a spark and air make a flame

By Jeffery Abdulateef\-Adoga

Topic: Machines

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

## Guide

### 1. Cigarette Lighter Assembly

A pocket lighter makes fire from three things: fuel, a spark and air\. Here are its parts on a work mat\. We will build it from the fuel tank up, then watch it light\. Tap any part to see its name\.

This is a model to explore\. Never take a real lighter apart: the fuel inside is under pressure\.

### 2. 1 · Fit the Gas Valve

The tank holds butane, a fuel squeezed so hard that it stays liquid\. Press the valve into the hole on top\. A tiny spring inside keeps it shut, so no gas escapes until the nozzle is lifted\.

### 3. 2 · Fit the Gas Lever

Lower the lever so its fork slips round the nozzle\. When your thumb presses the button, the lever tips like a seesaw\. Its fork lifts the nozzle a tiny bit, and that opens the valve\.

### 4. 3 · Drop In the Spring

Drop the coil spring into the narrow tube beside the valve\. It will push the flint up against the spark wheel, so the wheel always has something to scrape\.

### 5. 4 · Add the Flint

Drop the flint in on top of the spring\. It is not really flint but ferrocerium, a metal mix of iron and cerium\. Scrape it and it throws off specks that burn as they fly, as hot as 3,000 °C\.

### 6. 5 · Fit the Spark Wheel

Press the wheel down between its two supports\. Its rough steel edge rests on the flint and works like a tiny file\. The ridged rims on each side give your thumb a grip\.

### 7. 6 · Snap On the Wind Guard

Push the metal guard down over the nozzle until it clips on\. Its slots let air in to mix with the gas, and its walls shelter the flame from the wind\.

### 8. How It Lights

Roll the wheel: it scrapes the flint and throws sparks towards the nozzle\. Your thumb rolls on to the button, which opens the valve, and butane gas rushes out to mix with air\. The sparks light it\. Let go and the valve snaps shut, so the flame goes out\.

One small lighter can give up to about 3,000 lights\.