When performing carpentry or plumbing work, it is regularly required to measure various holes.
A conventional ruler is not very suitable for this, because it is difficult to measure, for example, a notch.
In addition, it gives an accuracy of up to 1 mm, and this is not always enough.
For more accurate measurements calipers are used, which allows to determine internal and external dimensions with an accuracy of 0.1 mm.
You will need
- The item to be measured
Look at the caliper. The most common of them consists of a rod with sponges. Sponges are fixed. There is a millimeter scale on the bar. Its length is 150 mm. On the rod moves the frame, on it are movable sponges. An auxiliary scale 19 mm long is located on the movable jaws. It is divided into 10 equal parts, the distance between the divisions is 1, 9 mm. This auxiliary scale is called a vernier. Before measurements, check the accuracy of the caliper by aligning the jaws. Zero marks of the main and supplementary scales should coincide, and the tenth stroke of the additional scale should coincide with the nineteenth prime stroke. The caliper allows you to measure the depth of the hole, for this there is a depth gauge on the back of the bar.
Secure the part in the vice. If there is no vice, fix it in any other way so that it does not move, otherwise the measurement will be inaccurate.
To measure external parameters, cover the partMobile and fixed sponges. Lightly press the sponge against the part so as not to cause mechanical damage and do not break the caliper. Secure the jaws with the support screw.
Look at the division of the basic scaleCoincided with the first nonius risk. This division indicates the number of whole millimeters of the part. Look at where the risks of both scales exactly match the next time. Count the divisions on the vernier. This number will denote a tenth of a millimeter, it must be added to the number of whole millimeters.
The internal parameters are measured by another pair of jaws that are inserted inside the notch. Counting is the same.