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The composition structure of the vernier caliper and the micrometer

Vernier caliper is a commonly used instrument for measuring length in industry. It can be directly used to measure the workpiece with high accuracy, such as the length, inner diameter, outer diameter and depth of workpiece.

An overview of the vernier caliper

As a widely used high precision measuring tool, the vernier caliper is made up of the main ruler and the cursor that can slide on the main ruler. If the scale value of the cursor is divided, the vernier caliper is also divided into three kinds, 0.1, 0.05 and 0.02mm.

The reading method of vernier caliper

For example, the precision vernier caliper 0.02mm is taken as an example. The reading method can be divided into three steps;

1)Readout the whole millimeter by the nearest scale on the left main ruler by the sub ruler and zero line;

2)The 0.02 readout decimal number is multiplied by the sub - ruler and zero line by the number of the lines at the right and the scale on the main ruler.;

3)Add up the two parts of the upper integer and the decimal part, that is, the total size。

Vernier caliper micrometer principle and.Ppt readings of the main scale minimum scale is 1mm, the vernier has 10 small scale divided their length equal to 9mm, the minimum degree of each index and the main scale vernier is 0.1mm, when the measuring feet together, the zero line and the main ruler of the cursor zero line reclosing,

The reading method of 0.02mm vernier caliper

As shown above, the scale of the 0 line of the sub ruler to the front of the main ruler is 64mm, and the ninth lines after the 0 line of the sub ruler are aligned with a line of the main ruler. The ninth lines after the 0 line of the auxiliary ruler indicate that:

0.02x9= 0.18mm



The method of using vernier caliper

Draw the claw together to see if the zero scale line is aligned with the vernier and the main ruler. If the alignment may be measured: if there is no alignment to remember: zero error zero line cursor on the right side of the ruler body is called the zero line zero error, on one side of the ruler zero line is called negative zero error (the provisions, regulations and methods the axis of the origin to right to left. As the origin of negative).

When measuring, the right hand holds the ruler, the thumb moves the cursor, and the left hand takes the object to be measured for the outer diameter (or inner diameter), so that the detected object is located between the outer measuring paws. When it is tightly linked with the measuring paw, it can read, as shown in the following figure.:

Application of vernier caliper

As a common measure, the vernier caliper can be applied in the following four aspects:

1)Measuring the width of the workpiece

2)Measuring the outer diameter of the workpiece

3)Measuring the inner diameter of the workpiece

4)Measuring the depth of the workpiece

See the following four aspects of the measurement:

Vernier caliper

1.Main ruler unit:cm

2.Minimum dividing value u

(1).Ruler: 0.1cm, and 1mm


A.10 diversity: 0.1/10cm=0.01cm

B.20 diversity: 0.1/20cm=0.005cm

C 50 indexing: 0.1/50cm=0.002cm

3.Reading: the measured value = readings of the main ruler A + cursor ruler reading B

Reading the main part from the ruler, that is, the scale of the scale on the main ruler of the zero scale line of the ruler, A

find out the alignment of the N scale line from the vernier ruler to a scale on the main ruler, the vernier

The screw micrometer is also called the micrometer. It is a precise measuring tool. Next, we will explain the principle, structure and usage of the screw micrometer.

What is a spiral micrometer?

Micrometer and micrometer (micrometer), micrometer, micrometer, is measuring the length of more sophisticated tools than vernier caliper, can accurately to use it to measure the length of 0.01mm, the measurement range of a few centimeters.

The structure of the spiral micrometer

The following is a schematic diagram of the structure of a spiral micrometer:

Working principle of spiral micrometer

he screw micrometer is made according to the principle of spiral amplification, that is, the screw rotates in the nut for a week, and the screw goes along the axis of rotation or a distance away from a pitch.So, the tiny distance moving along the axis of the axis can be expressed by the readings on the circle.

2)The left hand holding rack (C), turn the coarse adjusting knob D rod F and anvil A spacing is slightly larger than the analyte into the analyte, the rotation knob to clamp the protection of D 'analyte ratchet sound until now, a fixed knob G rod fixed after reading.

The reading method of the spiral micrometer

1、First read the fixed scale

2、Read the half scale again, if the half scale line has been exposed, it is recorded as 0.5mm; if the half scale line is not exposed, it is recorded as 0.0mm;

3、Read the movable scale again. Remember as n x 0.01mm;

4、The final reading results are fixed scale + half scale + movable scale

The spiral micrometer is also called a micrometer, because the result of the spiral micrometer reads exactly as a unit of mm.

Precautions of spiral micrometer

When measuring, pay attention to stopping the use of knobs when measuring the micro screw approaching the measured objects, instead of using the fine tuning knob to avoid excessive pressure, which can make the measurement accuracy and protect the screw micrometer.

•In reading, pay attention to whether a half millimeter line is shown on a fixed scale.。

•When reading, there is an estimated digit in thousand bits. It can't be thrown away. Even if the zero of the fixed scale is aligned with a certain scale line of movable scale, the thousand bit should be read as "0".

•When the small anvil and the micro screw are closed together, the zero point of movable scale does not coincide with the zero of the fixed scale, and there will be zero error. It should be corrected, that is, to remove the zero error value on the final length reading.

The correct use and maintenance of the spiral micrometer

•Check the accuracy of the zero line;

It is necessary to clean the surface of the workpiece by the measurement.

•Large workpiece should be placed in the V type or plate measurement;

•Clean the rod and the anvil before measuring;

•A ratchet device is needed when the movable sleeve is screwed;

•Do not unscrew the rear cover so as not to cause the zero line change;

•Clean the oil, put it in a special box, and put it in the dry place.。

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