Feeler Gauge


A Feeler gauge is used to measure the clearance between two parallel flat faces for example piston and cylinder. As the name suggests, feeler gauge called as to measure neither tide nor freely.

feeler gauge

Feeler gauges are used for measurement of clearances.

It is a tool that measures air or narrow gap widths between two surfaces in engines and machinery.

Feeler gauge available in no. of the blade like 10,13,20 and 28. With a step of 0.05 and 0.10 mm.


The feeler gauge has two major parts, a  body or block which acts like a protective case or shealth and a large number of blades of different thickness.

feeler gauge by stanley

The body is the base that holds the blades together. Feeler gauges are made entirely of steel so that they are corrosion free and the blades do not rust easily.

In machinery and engine service, it is important to predict accurate measurement of gaps for smooth performance and to avoid any faulty operations.

It is extensively and mostly used for measuring the gap between an engine cylinder and piston.

When there is extra gap even after a blade is inserted then the blades of the feeler gauge can be used in various combinations as per the requirement, that is different blades having different thickness can be stacked together and used.

The thickness of the blades are in fractions of mm and inches, usually ranging from 0.03 mm to 1mm.


On basis of the blades, it is of two types, tapered and parallel.

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The working of feeler gauge is easy. The blades are kept on the vacant gap that needs to be measured, initially one blade of standard thickness is kept, then if there are extra gaps other blades are adjusted and joined together and used.

Ensure that the blades can be easily pushed to and fro and are not tight nor free to move.

In order to have a problem-free measurement, the blades should be free of dirt and grease.

To maintain the blades for longer lifetime apply motor oil after every use.

2 thoughts on “Feeler Gauge

  1. thanks for this information 🙂

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