It seems Jats in ancient times worked with metal, till the time they started to settle down as farmers. It is obvious travelling/migrating people/nomads needed tools for their everyday work. Living life of nomads also meant having a self-dependency in metal works, as in ancient times, metal would have been a prized possession to cut your way through forests, cut meat, using metal for cooking and eating utensils, etc.
Nomadic metal workers in India are called Luhar, which becomes Lu+Har. Root word "Har" in IndoEuropean languages and going back to the primitivity of the languages, the word "Luhar" is "Luheer". Ancient IndoEuropean langauges spoke "e" as "a" as spelled in English word "Apple". These ancient metal working nomadic tribes took to different metal works at different points of time in history depending on the availability of metal and the need+discovery of metal.
It is also possible that these ancient nomadic tribes working with metal could have been founders of many kingdoms through out the world.
Are there are villages named with "Luhar", in which Jats and similar tribes reside?