Flat feeler gauges (see picture) are a set of plates of a certain thickness with corresponding markings, used to measure various gaps. Also, flat feeler gauges can be used, for example, to measure axial play where the use of a dial indicator (see below) is difficult.
The flat feeler gauge set must be protected from excessive force and impact to prevent the feeler gauge plates from being bent or damaged. The surface of the flat feeler gauges must be kept clean and coated with a thin layer of oil to prevent corrosion.
When measuring the gap, it is necessary to select a flat feeler gauge that will fit with little resistance between the two parts. It is recommended to have two sets of flat feeler gauges to ensure accurate measurements.
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