How to measure the diameter of any wire if there is no vernier caliper? I show a simple old-fashioned way

Every home craftsman sometimes faces a problem when the necessary tool is not at hand and one has to look for a non-standard solution for the task at hand. For example, you need to find out the diameter of some wire (wires) and the best way to do this is to use a vernier caliper. But what if he is not at hand? In fact, there is nothing complicated here and now I will show you the old-fashioned way, with which you can measure the diameter of any wire with an accuracy of hundredths of a millimeter. Nor do you need a caliper.

I'll take a piece of wire as an example. To make the measurements more accurate, you will need a longer wire (20 - 25 cm).

Remove the insulation and take out the copper wire.

To find the diameter of this wire, we only need a ruler or tape measure, which any home craftsman has.

No, do not think that we will measure the diameter of a wire simply by leaning it against a ruler. Of course, this can be done and the approximate diameter can be determined by eye, but the error in this method will be large, and we want to get an accurate result.

In addition to the ruler, we also need a pencil, a screwdriver or some kind of round pipe of a small diameter.

Now, hold one end of the wire with your finger and wind it around the pencil (if the wire is very stiff, you can clamp it together with the pencil in a vice).

We wind the wire so that each subsequent turn fits snugly to the previous one. In total, you need to make about 20-25 such turns (the more turns you make, the more accurate the result will be).

In my case, it turned out 23 turns. Then we take a ruler and measure the length of the resulting turns. My length came out a little more than 32 mm, but I need to make it so that the value turns out to be an integer. Therefore, I will add a few more turns.

Adding two more turns, I got a length equal to 35 mm. Great, there is an integer.

This completes the necessary measurements. Now everything is simple, we divide the resulting length (35 mm) by the number of turns (25) and we get a value (1.4 mm) equal to the diameter of our wire. In the example I used a 1.5 mm² wire. I'm sure many people know that the diameter of a copper core in such a wire is 1.38 mm, which means that in this way we were able to find its diameter with an error ± 0.02 mm. Agree, quite an accurate result!