In the last decade there was a resounding change in the way companies produce. The customer became fundamental and with it the quality of the products. It is that by increasing competition, quality provides a very important competitive advantage .
If we talk about parts in which dimensions are key to outstanding quality, such as screws , nuts, washers, pistons , among others, an accurate measurement element is essential. One of the most accurate is the micrometer. This is why it is important to know how it works and how to make a correct measurement.
What is a micrometer?
A micrometer, also called a screw or Palmer gauge, is a measuring element that bases its operation on a screw that is used to determine the dimensions of an object with very high precision. Its name comes from the Greek μικρο meaning “micros” and μετρoν “metron” meaning measurement.
Precision of a micrometer
The precision of the micrometer is between 0.01 mm and 0.001 mm depending on the type of micrometer. This means that it divides the millimeter into 100 or 1000 parts . So we can know the size of an object measured with a micrometer, we can give an accuracy of up to 1/1000 mm , that is, we can know, for example, that it measures 13.5437 cm or 135.437 mm.
What is a micrometer used for?
As we mentioned in previous paragraphs, a micrometer is used to measure the dimensions of objects with an accuracy of between 1/100 and 1/1000 mm.
This is why micrometers are widely used in metallurgical companies, mostly those that produce bolts to accurately determine whether their products meet the specified measurements or not.
How does a micrometer work?
The basis of operation of a micrometer is the same as that of a nut on a bolt . As we adjust the nut, it gets more and more into the screw. The same thing happens with the micrometer.
As we turn the mobile drum, it makes the pin move towards the stop. Once the pin comes into contact with the object to be measured, the clamping lever must be lowered , and everything is ready to read the measurement.
Below is a video that explains step by step how a gauge works and how to take a measurement with it.
How do you read a micrometer?
When we talk about reading a micrometer we are talking about mechanical micrometers, since with digital ones a computer is in charge of making the calculations and displaying them on the screen.
To better explain how to read a micrometer, we are going to see an example.
Suppose we have the following measurement
To determine the value of this measurement, we must first look at the fixed drum, in this case the left side of the image. We see the number 15. From the number 15 to the next line that is at the top there is a millimeter. From 15 to the hairline that is at the bottom there is half a millimeter.
We see that the moving drum (right part) cuts the fixed drum a little after 16 and after the line that marks 0.5. So we are talking about a measurement of 16.5 mm. To continue with the precision, we turn to the moving drum.
We see that on the scale, the first little line coincides with the middle line of the fixed drum. This means that we are talking about 0.01 mm more. Therefore the measurement of this micrometer gave us 16.51 mm .
Parts of the micrometer
- Body: It is the part that holds all the other elements of the micrometer. It has to absorb possible dilations due to heat .
- Top: This part is fixed and is the one that determines the 0 point of the measurement. That is, from this point the measurement will begin.
- Spike: It is the moving part that adapts to the measurement and determines the reading of the measurement
- Fixation lever : Fixes or lets the pin move
- Ratchet: Limits the force that is applied during the measurement
- Mobile drum : It is the mobile scale that moves until it stops. It has 50 divisions
- Fixed drum: The fixed scale that goes from 0 to 25 mm is engraved.
There are many types of micrometers that are divided according to different characteristics.
according to technology
- Mechanical Micrometers: The entire micrometer works on a mechanical basis. It is the most durable micrometer.
- Electronic or digital micrometers : Electronic and digital technology is used to perform the measurement. In addition, the results are thrown digitally. It is very expensive.
according to normalization
- Standard normalization: They use in a general way the amplitude and appreciation
- Special standardization: Used in manufacturing processes or for verification, so they have a range of measurement and special appreciation.
According to the unit of measure
- Decimal system: the unit of measurement used is the millimeter
- English system: the unit of measure used is the inch
Depending on the measurement to be made
- outside micrometers
- inside micrometers
- depth micrometers