Use and maintenance of universal measuring tools

Some common maintenance methods and precautions for measuring tools can be avoided; 1. Outer diameter micrometer; 1.1 Before use, the zero position must be checked. If it is not at the zero position, it should be sent for measurement; 1.2 Due to dust, debris, and oil causing errors of several micrometers; 1.3 During measurement, the object being measured must lightly contact the measuring head, if touched; 2. Dial gauge and dial indicator; 2.1 Before use, the measuring surface and measuring rod of the dial gauge should be wiped clean; Before using the dial gauge, the measuring head should be compressed so that the pointer rotates by at least 1; 2.3 The stability of the indicated values should be examined first before proceeding

Some common maintenance methods and precautions for measuring tools can avoid unnecessary losses and prolong the service life of the measuring tool.

1. Outer diameter micrometer

1.1 Before use, the zero position must be checked. If it is not at the zero position, it should be sent to the measuring room for zero adjustment.

1.2 Due to dust, debris, and oil causing errors of several micrometers, the measured object must be wiped clean with gasoline or a soft cloth or paper before measurement.

1.3 During measurement, the measured object must gently contact the measuring head. If the collision force is too strong, it should be returned a bit.

2. Dial gauge and dial indicator

2.1 Before use, the measuring surface and measuring rod of the dial gauge should be wiped clean.

Before using the dial gauge, the measuring head should be compressed so that the pointer rotates at least 1/6 turn.

2.3 The stability of the indicated value should be checked before use. At the zero position, the measuring rod should be moved down quickly or slowly. At this time, the change in the indicated value should be observed. When the indicated value changes by more than 0.3 scale, the following issues should be considered: a. whether the bracket is loose; b. Is the clamping part of the dial gauge clamp loose; c. If there are no first two situations, then there is a problem with the dial gauge itself, please refer it to the metrological verification personnel for handling.

3. Lever dial indicator and lever dial indicator

3.1 Keep clean, do not wipe oil on the measuring surface and rotating shaft.

3.2 After the meter is installed on the measuring station, the measuring head should be moved to observe the stability of the needle reading, and the dial should be rotated to align with the desired "zero position" to proceed with the measurement.

3.3 When using, pay attention to making the axis of the measuring head perpendicular to the measured dimension line. If for some reason, the axis of the measuring head cannot meet the requirements, the number read should be multiplied by cos α （ α— Correction of the angle between the axis of the measuring head and the measured surface

4. Inner diameter gauge

The inner diameter dial gauge is a precision measuring tool for measuring the size of inner holes, which can be used to measure the size deviation and the roundness and cylindricity deviation values of holes within the range of 6mm to 450mm. It is one of the indispensable measuring tools in the industrial sector.

4.1 According to the size of the measured workpiece, corresponding interchangeable measuring heads should be selected.

4.2 Install the inner diameter special gauge into the gauge holder and compress it by one turn, then tighten the locking screw on the gauge holder.

4.3 Select the corresponding calibration ring gauge or outer diameter micrometer according to the measured aperture to adjust the zero position of the inner diameter dial gauge.

4.4 Turn the inner diameter dial gauge from the calibration ring gauge or outer diameter micrometer into the measured hole, hold the handle, and make the inner diameter dial gauge swing slightly back and forth in the measured hole. At this time, the minimum reading value on the inner diameter dial gauge is the diameter size error of the measured hole.

5. Vernier caliper

5.1 Before measurement, the measuring surface and guiding surface of the caliper should be wiped clean;

5.2 Move the ruler frame until the measuring surfaces come into contact with each other. Check the overlap of the "zero" mark on the ruler body and the vernier.

5.3 During measurement, excessive measuring force should not be used. It should be gently pushed and slid through the belly of the mother finger, otherwise it will affect the measurement accuracy.

5.4 When reading the measurement results, the direction of the line of sight should be as perpendicular as possible to the scale surface.

6. Vernier caliper with meter

When measuring, gently apply the measuring force while moving the measuring claw up, down, left, and right, and then take the minimum value as the measurement value.

6.2 Attention when reading: a Align your eyes with the center of the dial gauge; b. At this position, move the eyeballs to read

The scale of the main ruler; c. Similarly, move the eyeballs to read the dial indicator value.

7. Height vernier caliper

7.1 Before measurement, the measuring surface and guide surface of the caliper should be wiped clean.

7.2 Special inspection plates should be used.

7.3 Contact the measuring surface with the inspection plate and check the overlap of the "zero" mark on the ruler body and vernier.

7.4 Use the scoring claw as lightly as possible.

During measurement, excessive measuring force should not be used, otherwise it will affect the measurement accuracy.

7.6 When reading measurement results, the line of sight should be as perpendicular as possible to the scale surface.

The usage methods and precautions introduced above should be further adjusted and improved in combination with practice to achieve higher accuracy requirements, and can further comprehensively protect factors such as the texture of the measuring tool itself and extend its service life.

Measuring tools are tools used to measure the size of workpieces, such as calipers, block gauges, plug gauges, and micrometers. Due to the frequent friction and collision of workpieces during the use of measuring tools, and the fact that the measuring tool itself must have very high dimensionality and constancy, the following performance is required:

(1) High dimensional stability to ensure the constant shape and size of the measuring tool during use and storage.

(2) High hardness and wear resistance. This ensures that it will not be quickly worn out and lose its accuracy in long-term use.

(3) Sufficient toughness to ensure that the measuring tool is not damaged due to accidental factors such as collisions during use.

(4) It has corrosion resistance in special environments.

In production, measuring tools are like weapons in the hands of inspectors. If the weapon is in a semi paralyzed or damaged state, the inspection results are meaningless and do not play a supervisory and control role in product quality. So the maintenance and care of measuring tools are very important. Here are some maintenance specifications for measuring tools (applicable to commonly used testing tools):

1. Do not use oilstones or sandcloth to rub the surface of the measuring tool, as well as the measuring surface and marking parts. Non metrological maintenance personnel are strictly prohibited from disassembling, modifying, and repairing the measuring tool without authorization.

2. The storage location of measuring tools should be kept clean, dry, without vibration or corrosive gases, and should be far away from places with large temperature changes or magnetic fields. The measuring tools stored in the measuring tool box should be clean and dry, and no other debris should be stored.

3. Do not touch the measuring surface of the measuring tool with your hands, as damp dirt such as sweat can contaminate the measuring surface and cause it to rust. Do not mix measuring tools with other tools and metal substances to avoid damaging the measuring tool.

4. After using the measuring tool, clean the surface stains and aluminum shavings, loosen the fastening device, and apply anti rust oil to the measuring surface when not in use for a long time (more than 1 month). When measuring tools are not in use, they should be placed in a protective box, dedicated personnel should use them full-time, and annual audit records of measuring tools tested by authoritative units should be kept.

5. It is not allowed to use the measuring claw tip of the caliper as a scribe, compass, or other tool, and it is not allowed to manually twist the two claws or use the measuring tool as a caliper.

When there are burrs on the surface of the workpiece, it is necessary to remove them before measuring, otherwise it will cause wear on the measuring tool and affect the accuracy of the measurement results.