Micrometer readings are an important part of precision measurement, and there are many misconceptions about
whether the integer part of the micrometer should be above or below. Today we will answer this common misconception
and explain in depth the correct use of micrometers.
Ⅰ、Micrometer construction and reading principle
1. Micrometer is a precision measuring instrument, mainly used to measure the length, thickness or diameter
of the object. It consists of a fixed anvil, a differential cylinder, a force measuring device and so on.
Understanding the structure of the micrometer is the basis for correct reading.
2. Micrometer reading principle based on the principle of spiral micrometer. The micrometer cylinder rotates
for one week, the micrometer screw moves 0.5mm, and the scale on the micrometer cylinder is divided into 50 frames,
so each frame represents 0.01mm.
3. When reading, we need to read the fixed scale and differential cylinder scale at the same time.
II. Position of the integer part: below
1. The fixed scale of the micrometer is located on the sleeve, and the scale of the integer part
is located below the sleeve.
2. Never mistake the upper exposed portion for the whole number portion. The upper exposed portion is actually
part of the next whole number scale and is used to indicate the next whole number scale that the micrometer
barrel is about to reach.
3. Remember, the integer part is always below!
Ⅲ、Correct reading of the micrometer display value
1. First read the whole number part of the scale below the sleeve. For example, if the scale is aligned with
the number “5”, the integer part is 5mm.
2. And then read the scale on the differential cylinder. For example, if the graduated line of the differential cylinder
is aligned with the number “25”, the reading of the differential cylinder will be 0.25mm.
3. Finally, add up the integer part and the differential cylinder reading to get the final measurement result.
For example, 5mm + 0.25mm = 5.25mm.
Ⅳ、Common misunderstandings in the use of micrometers
Mistake 1: Mistaking the scale above the sleeve for the whole number part. The correct integer part of the scale
is located below the sleeve.
Mistake 2: too much or too little force when reading. Use micrometer measurement, should maintain
the appropriate force, too large or too small will affect the measurement accuracy.
Mistake 3: Do not pay attention to the micrometer zero adjustment. Before use should check the micrometer
zero position is accurate, if deviation needs to be adjusted.
V. Maintenance Tips
1. After use, the micrometer should be wiped clean and coated with anti-rust oil.
2. Avoid collision and extrusion when storing to avoid damaging the precision parts.
3. Regular calibration to ensure the accuracy of measurement.
