The resemblance of Tinkatink to a young human child is not accidental, nor was it shared by this pokemon's wild ancestors. Tinkatink rely extensively on the metal tools which they spend most of their time forging, both to prepare food and to defend themselves, but a hammer which is a lifeline to a Tinkatink is a delicious ingot to an Aron or an Orthworm, and the fae have always struggled against steel. Fortunately for Tinkatink, human dwellings are more than capable of sheltering these pokemon, and they make ample use of discarded tools which are not up to these pokemon's exacting standards.
Human blacksmiths are known elsewhere in the world, but in Paldea it is the domestication of Tinkatink which marks the coming of the Iron Age. The disappearance of the Melmetal was not nearly as painful in this region as elsewhere, for the smaller but much more numerous Tinkatink quite effectively replaced them. It is, however, quite telling that Tinkatink are not found in earlier periods; Bronze Age Paldeans considered these pokemon a pest to be chased away, no less harmful to their tools than Aron. Worse, this comparison, which is attested in ancient artwork, surely grievously offended these pokemon, who despite their youth possess all the pride associated with fairy types.
The creation of the modern Tinkatink, and their habit of shaping metal into forms useful to humans, was a process of trial and error which lasted many generations; gradual improvements in the Tinkatink toolkit, and increasing demand for their wares as trade goods, continued down to the Industrial Revolution. Mass production in factories has put the Tinkatink out of artisan work, but these pokemon fared better than their human counterparts; increasing societal wealth has allowed them to take on a new role as a beloved household pet!