For those of us who are into cars, we usually have a fascination for how things work. Most of us have some sort of story of taking apart their parents power tools, just to see what was on the inside. You can take that a step further and wonder, how is that drill made?
The Science Channel has a popular TV series called “How Its Made,” that covers everything from plastic cups to toilet paper. They take you inside a factory and show the manufacturing process for those items.
In this episode, they check out how spark plugs are made. To start the manufacturing of a spark plug, they begin by making the ceramic insulators. This is usually the white part of the plug, but can be painted other colors as well. While the insulators are in the kiln being fired, they start by making the metal body of the plug. This is done with raw steel that is repeatedly pressed into dies until the final shape is achieved.
Once the metal body has been formed, they add the nickel alloy tip to the plug. From here, the metal body goes through a set of threaded rollers that emboss the threads onto the body, allowing the body to screw into a cylinder head.
Now the ceramic insulators receive the electrode, which runs the entire length. At one end, the spark plug wire will attach and the other end will fire the fuel. With the electrodes pressed into the plug, the metal body now slides over the insulator with the help of some oil. A shrinking tool applies electrical current to fit the metal body tight against the ceramic insulator.
The last step is for the nickel alloy tip to be bent over, within a few thousandths of an inch from the electrode. With manufacturing complete, the plugs go into boxes and off to your local auto parts store.