Use and measure with caliber, king's foot or vernier

In this tutorial I will explain the use of one of the most used instruments in the workshop to make measurements: THE CALIBER, KING OR VERNIER.
We generally use the caliber to measure parts, screws, axle diameters, holes, seals, and anything we need to know its dimensions with some precision, which usually ranges from 0.1mm to 0.02mm depending on the instrument.

Different types for different needs
There are different types of king's foot: universal (such as the one we will use below), with graduated sphere,

digital,

deep,

of gears ...

Caliber allows us to make internal, external, and also deep measurements. To achieve maximum accuracy, it is essential that the caliber be fully straight and level with the surface to be measured.

Know the parts of the caliber
Even if only to acquire some technical culture, it is interesting to know how the different parts of this instrument are called.

1. Outdoor palpators
2. Interior palpators
3. Depth probe
4 and 5. Graduate rule (in mm and inch)
6 and 7. Nonio or Vernier (in mm and inch)
8. Displacement button

To measure!
We will explain how to make a measurement through a practical example. In this case, our king's foot has a 5 -hundredths precision of a millimeter (0.05mm).
We can observe the value in the following photo:

In this case we see where the 0ono mark is and we count the complete millimeters in the rule, they would therefore be 32mm.
Then we have to look at the only brand of the Nonio that perfectly coincides with a brand in the rule, in this case it would be 7, so the measurement value is 32 + 0.70 = 32.70mm.

We see another example in the following image, where the 0 of the Nonio is behind the 8MM and the brand of the Nonio that coincides exactly with another in the rule is the one between the numbers 3 and 4, so we have 0, 35mm more.

In this case the measurement would be 8.35mm.
The following photograph indicates an exact measurement, since in this case both brand 0 and brand 10 with the rule coincide, and the measurement is 15.00mm.

Instrument care
It is important to clean the caliber when we have finished using it, and pass a slightly wet rag in oil, since the sweat itself is corrosive and can accelerate its oxidation. Do not store it with the palpators fully closed for the same reason.
With these simple tips you will have a reliable precision instrument that will last many years.

Frank Burguera

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