There are many different measuring instruments that we use at home, at school, at work. Among them, not the last place is occupied by a tool called a micrometer. This small-sized device (Fig. 1) is distinguished by the highest precision and is used under production conditions for measuring parts with high accuracy. The device can be wrong in the range of 2-9 microns (micrometers). If we consider that 1 micron is equal to a millionth of a meter, then this is a very high accuracy, much higher than that of a conventional caliper.
Figure 1. The micrometer has a sufficiently high accuracy and is used in production to measure parts with high accuracy.
Micrometer is a device that is produced for different purposes. Instructions attached to the instrument gives a complete description of this device. Micrometer can be:
The device tube micrometer.
- Common, which measure the outer diameter and thickness of parts.
- Pipe, designed to measure the thickness of the pipe walls (Fig. 2).
- Sheet, with which carry out measurements of the thickness of the sheet material.
- A tooth micrometer is needed to measure the elements of gears.
- Limit micrometer allows you to set the microscrews on different sizes in accordance with the tolerances.
- Prismatic tool designed to measure parts and products with an odd number of surfaces - taps and reamers.
- Wire is used to measure the diameter of the wire, all sorts of balls up to 10 mm in diameter.
- Threaded measures threads of different shapes. It has several interchangeable inserts (Fig. 3).
- Tool for measuring recesses, grooves with small dimensions. Equipped with thin working jaws.
- The micrometer for measuring small-sized products and parts is equipped with a wide base.
- Universal. Measures various surfaces with replaceable inserts having different shapes.
- Grooving. Measures the width of the grooves and the distance between them.
- Micrometer is used to measure the depths and heights of various protrusions.
- The lever tool is an analogue of the lever bracket.
- Micrometer. Designed to accurately measure the value of products in high temperature conditions.
- A micrometer used to measure distant surfaces of a part.
- Tool for measuring the thickness of the brake discs.
- Digital. Made to measure the thickness and diameter of parts. The button turns on and off the digital display. On some models there is also a familiar scale on the screw (Fig. 4). There are models with a built-in calculator.
- The micrometer nutromer serves for control at the same time 2 points. It has many attachments. Measures grooves located vertically and horizontally.
There are other types of this tool used in more specialized conditions.Back to table of contents
How to use a mic
There are many types of tools. Micrometers can be large and small, mechanical and electronic. The most common option is a mechanical device MK 25. How to use it?
Threaded micrometer device.
- check measuring instrument;
- move the micrometer and insert the part between its jaws;
- hold the part with a drum, then rattle until clicks appear;
- see the values on the scale.
All these actions can be placed in the instruction:
- Typically, a micrometer consists of a bracket that serves as the base, and a screw pair. In the bracket is the stem and the heel of the device. A rotating drum and ratchet are attached to the screw. Screw stops after measurement.
- If necessary, the device must be cleaned of impurities and dirt.
- To prepare the device for operation, it is necessary to take it in hand and rotate the drum to dilute the contact surfaces. The gap between them should slightly exceed the size of the measured part.
- To bring the screw closer to the heel, you need to rotate the drum in the direction of the clockwise movement.
- The measured part is clamped by rotating the drum and the ratchet to a few clicks.
- Read the readings on the scale.
Micrometer periodically need to be checked. This is done very simply. You just need to twist the drum and ratchet without parts until it stops. The number 0 must fully coincide with the central mark on the stem. If the coincidence cannot be called ideal, you need to twist the stem with a special key that is included in the kit. It is advisable to measure those parts that were at least 3 hours in the room with a micrometer.
Digital micrometer device.
Let's try to measure the drill. On the shank its size is specified, but not always easy to read. And the class of their accuracy is different. The drill is inserted and clamped by turning the micrometer drum. For a more accurate measurement, you need to wrap the ratchet before 2-3 clicks appear.
For taking readings, there is a scale on a stationary stem and a rotating scale on the drum. The price of each division on the bottom scale is 1 mm. Dividing the scale of the drum shows hundredths of a millimeter.
Measuring and reading data for all types of tools are practically of the same type. The micrometer allows you to fix this value to compare this size with the size of other parts from the batch.Back to table of contents
- It is recommended to measure only clean, smoothly machined parts. They should not be metal and emery dust.
- Do not measure hot parts. Measurement results will not be entirely accurate.
- After work, the micrometer must be carefully wiped and put in a wooden case along with accessories.
- Before long storage, the device should be washed in clean aviation gasoline, wiped and lubricated with petroleum jelly.
- Store the device in a dry place free from temperature fluctuations.
Micrometer is a tool that is not always possible to find in the home workshop.
It is needed in production. The tool is quite accurate, has many varieties depending on its purpose. It is very easy to use if you follow all the instructions and recommendations.