How to Convert a Metric Feeler Gauge to Standard

Things You'll Need

  • Metric feeler gauge

  • Mechanical gap

  • Calculator

Feeler gauge blades are either sheet metal or wires.

Correct measurements of any tight tolerances are a necessity to ensure the proper operation of your mechanical and electrical equipment. Feeler gauge blades have the width -- in metric or standard units -- of the blade stamped near their base. When using a feeler gauge with only metric sizes stamped on the blade, you can still determine the standard size by converting the metric dimension. A simple mathematical equation allows you to precisely convert a metric dimension to a standard equivalent.

Step 1

Slide one blade of a metric feeler gauge into a mechanical gap to determine the gap width. The correct blade will slide into the gap while slightly contacting the top and bottom of the gap.

Step 2

Read the number stamped on the bottom of the feeler gauge blade matching the size of the mechanical gap.

Step 3

Enter the metric measurement into a calculator. Multiply the metric number by 0.039 to convert the metric dimension to standard units. For example, a feeler blade 3 mm thick multiplied by 0.039 equals 0.117 or 3/32 inch.