How To Read The Hex Bolt Size Using A Vernier Caliper

Vernier calipers, a commonly used tool for measuring hex bolts, are usually accurate to 0.01 cm, but are more complex than tape measures. People who have just contacted may not be able to touch the door immediately. . This is a brief introduction to the correct use of downstream standard calipers.

Method 1 Method of use

Measure the outer diameter and clamp the item as shown to obtain measurement data.


The inner diameter is measured, as shown in the figure, in the inner diameter portion of the article, both ends are opened to support the article, and the measurement data is obtained.


Measure the depth, as shown in the figure, after the red frame part is probed into the thing to be measured, fix the ruler and obtain the measurement data.


Method 2 Reading method

First, look at the position of the sub-foot "0", which determines the first two digits. In the figure, 0 is behind 2.3 cm. That is, the inner diameter of the measuring object is 2.3xxcm.

Then observe the sub-scale division (accuracy), that is, how many grids are 20 divisions, that is, the accuracy is 0.05mm. (Units per division = 1 mm / division)


Then look at the digits where the sub-foot and the main ruler are completely coincident. Look inside the red box, and the coincident part is 2 squares. That is, the coincidence is 17. 0.05mm per unit, the final digit, 0.85mm (0.085cm), so the last

measured in the legend, the target inner diameter is 2.385cm