Viktor, Ingore the humorists. Yours is a worthy question; if you don't know, ask. You came to the right place.
But you need to refine your question. What kind of caliper? Over here in the colonies we have several kinds of calipers.
There are spring and firm jooint calipers you use to transfer measurements from part to a measuring instrument like a scale or ruler.
There are vernier and plain calipers where the two jaws are closed on the surfece to be measured and the reading taken from the engraved scale on the beam of the tool.
There are micrometers where a screw and graduated thimble mounts in a C shaped frame. The work is placed between the spindle, the svrew and thimble adjusted for light contact with the work netweem the spindle and anvil. The rough reading taken from a scale on the barrel and the thousandths of an inch (or .02 mm) taken from the thimble. I'm using US terminology. I don't know the Swedish or Continental English equivelents.
Anyway, screw micrometer frames are usually iron castings in larger sizes. Other parts are made from bar stock, sheet stock, or forgings. There are many different processes used to make the various parts.
Spring and firm joint calipers are now made from flat sheet stock. I've made a few calipers with nothing more than common metalworking hand tools and a screw and nut for the firm joint pivot.
