How to Read a Micrometer Scale?

[AvaMarie]

Reading steps for a micrometer are as follows: Read the scale on the fixed sleeve corresponding to the left end face line of the movable sleeve; Align one of the scale lines on the movable sleeve with the zero reference line on the fixed sleeve and read the scale; Add the readings of the above two scales. Below is a detailed introduction to micrometers: Brief Description: A micrometer, also known as a screw gauge, screw micrometer, or micrometer caliper, is a more precise tool for measuring length compared to a vernier caliper. It can measure lengths accurately up to 0.01mm, with a measurement range of several centimeters. Classification of Micrometers: Micrometers can be divided into mechanical micrometers, electronic micrometers, vernier reading outside micrometers, small head outside micrometers, pointed head outside micrometers, wall thickness micrometers, sheet thickness micrometers, and micrometers with a micro head to be measured, among others.

[VonEmilia]

I recently started learning how to use a micrometer, and my teacher taught me a simple method: first, look at the scale on the fixed sleeve, which represents the whole number part. For example, if 5 mm is visible, then check if the half-millimeter line is exposed. If it is, add 0.5 mm, making it 5.5 mm. Next, observe the scale on the movable sleeve, where each small division represents 0.01 mm. For instance, if it points to the 18th division, that’s 0.18 mm. Don’t forget to estimate the last decimal place by looking horizontally at the position of the movable sleeve between two lines. I often estimate to the thousandth place—for example, if it’s one-third to the right between the 17th and 18th divisions, I’d read it as 0.175 mm. Finally, add the whole number and decimal parts together—for example, 5.5 mm plus 0.175 mm equals 5.675 mm. With a bit of practice, you’ll get the hang of it.

[Naomi]

With twenty years of experience in mechanical machining, I'm well-versed in micrometer readings. First, clearly observe the integer millimeter marks on the fixed sleeve, then pay attention to whether the half-millimeter line is visible. Each division on the thimble represents 0.01 mm – make sure to align it squarely with the scale to minimize parallax error. The most critical part is estimating the next decimal place; I usually judge by the proportion of the thimble's edge between two scale lines. For example, if the scale points to the 20.5 position, it's essentially 0.205 mm. When summing up, don't forget to include the half-millimeter line – my apprentice once forgot to add that 0.5 mm, resulting in scrapped parts. Always remember to clean the measuring surfaces before use, and avoid excessive pressure during measurement to maintain accuracy.

[KylieRose]

In our laboratory, we use a micrometer to measure metal sheets. Taking a 0.01mm precision model as an example: the fixed sleeve shows an 8mm scale, with no half-scale line visible; the movable sleeve points to the 36th scale line, which is 0.36mm; then estimate one-third of the way between the 36th and 37th scale lines on the movable sleeve, adding 0.003mm. The final measurement is 8 + 0.36 + 0.003 = 8.363mm. Note three points: keep your line of sight perpendicular when reading, gently tighten the micrometer screw without applying too much force, and calibrate the zero position for micrometers of different ranges. This precision is sufficient for inspecting the tolerances of mechanical parts.