What are Micrometers? How they work?

Amicrometer is a tool that measures the size of a target by gripping it. Some models are capable of taking measurements in units of 1 mm. Unlike calipers, micrometers apply the Abbe principle, allowing them to offer more precise measurements.

Generally, the term “micrometer” refers to exterior micrometers. However, there is also a variety of micrometers, suitable for various applications. We also note interior micrometers, bore micrometers, tubular micrometers and depth micrometers. The measurement range is always 25 mm but varies according to the size of the frame (0 to 25 mm or 25 to 50 mm for example), it is therefore essential to use a micrometer adapted to the size of the target. Recently, micrometers have gone digital.

How does a digital micrometer work?

There are two types of micrometers on the market: analog and digital, which can be used for the different micrometer models depending on the measurement to be carried out, exterior and interior parallels, exterior and interior cylinders, special cylindrical pieces, and for height and depth measurements. To help you adapt to the handling of the digital micrometer, I am going to explain how it works; Thus, when you buy one of these instruments, have a useful guide at the time you go to use it.

How to measure with a digital micrometer?

A digital micrometer is a portable tool, with which it is possible to make very precise measurements of lengths between its two measurement contacts, with an accuracy of up to one-thousandth of a millimeter, being able to express the measurement value in mm or inches.

Digital micrometers are used mainly to carry out measurements in the industrial area, or in dimensional metrology laboratories. They comprise a measurement range from 25 mm to more than one (01) meter, and their standard resolution is 0.01 mm, although they can handle resolutions of 0.001 mm (0.00005 inches).

Operation of a digital micrometer

The way to carry out measurements with a digital micrometer is the same as in those that are analog; but, in digital models, these have an LCD screen, where a direct reading is shown, indicating the exact value of the measurement digitally. Some models also have the scales engraved on their structure.

The working principle of the digital micrometer is similar to that of a screw and a nut. Rotating the ratchet causes an axial movement that advances the spindle 50 hundredths for each full rotation (360 degrees). Also, know the parts of a digital micrometer and verify that yours is complete.

Tips and recommendations before, during, and after using the digital micrometer

Before making the measurement, we must clean the anvil and the spindle surfaces with a clean cloth, to remove dirt and dust from these points; thus we achieve accurate measurement results. We should not use organic solvents such as acetone or benzene to clean it.

• Before using the micrometer we must thermally stabilize it at room temperature.
• We must not exert excessive force on the instrument; the stops should never be adjusted against the object being measured, using the drum; this should only be used to bring the plates closest to the object, and then complete the measurement with the ratchet knob.
• The instrument should be held only by the thermal insulation plates found on the body. It should never be taken by the ends, because the body heat will expand the metal, causing alteration of the distance and the measurement.
• Do not remove the part from between the stops without first separating them from them, otherwise, it could force them, causing scratches on the plates, thus losing the calibration of the instrument.
• Do not use the instrument near magnetic fields or high voltage areas.
• Do not expose the micrometers to direct heat, excessive humidity, or corrosive environments or with suspended particles, keep them in their respective cases for better conservation.
• It is recommended to clean the instrument frequently, using a cotton cloth and a neutral cleaning product, avoiding that the product penetrates inside the mechanism.
• The recommended calibration interval for micrometers is 3 months to 1 year.

Measurement method with a digital micrometer

• The procedure to measure is direct, placing the piece or object to be measured between the anvil and the spindle.
• The micrometer should be held by holding the frame by the heat insulating plate with the thumb and index finger of your left hand.
• First, we place the part that we want to calibrate against the support tip of the anvil, and then we proceed to rotate the drum to bring the spindle or tenon closer to the object.
• When the spindle or spindle is close to the object, with the index fingers and thumb of the right hand we turn the ratchet knob until it makes contact with the body we are measuring, until it is fully clamped between the anvil or fixed stop and the spindle.
• At the previous point, we continue turning the ratchet knob gently until we hear three clicks, which will indicate that we must stop turning the ratchet.
• When the anvil and the spindle have firmly trapped the object that we are measuring, then we will fix the measurement obtained using the lever or fixing or brake nut, thus avoiding that the reading taken is altered by some unwanted movement that causes a Measurement error.
• As soon as we have the micrometer locked, we proceed to make the reading on the screen, being able to compare it with the measurement recorded by the instrument on the scales, in case it has them.
• Finally, we unlock the brake lever and turn the drum in the opposite direction to release the object from the micrometer without causing alterations in the instrument.