Feeler gauge set

A feeler gauge is a simple tool used to measure thicknesses. Feeler gauges are mostly used in engineering to measuring the clearance between two parts. This page discusses common devices known as tools, for other meanings see Tool (disambiguation) Modern hammer A tool is, among other things, a device that provides a mechanical or mental advantage in accomplishing a task. ... Engineering is the application of science to the needs of humanity. ...

They consist of a number of small lengths of steel of different thicknesses with measurements marked on each piece. They are flexible enough that, even if they are all on the same hinge, several can be stacked together to gauge intermediate values. Its common to have two sets for imperial units and metric measurements although the pictured set has both measurements recorded on each blade. The Imperial units are an irregularly standardized system of units that have been used in the United Kingdom and its former colonies, including the United States and Commonwealth countries. ... See: International System of Units, colloquially called the Metric System, and also metrication. ...

A common application of this device is to set the gap in spark plugs to the correct size—this is done by increasing or decreasing the gap until the gauge of the correct size just fits inside the gap. This article or section should include material from Spark gap A spark plug is an electrical device that fits into the cylinder head of some internal combustion engines and ignites compressed aerosol gasoline by means of an electric spark. ...

The lengths of steel are sometimes called blades, although they have no sharp edge.