The Blacksmith clan (japanes name later)

This clan works in the ground around Konoha. They work as miners and blacksmiths. They are famous for create the best weapons in Konoha and they are the biggest seller of shurikens and other ninja weapons. They abilities are to form iron under high temperature, that they create with their chakra, into whatever they want. Their bloodline limit is the iron body, which makes their body as hard as iron. They can also form iron with chakra, but that is a high level jutsu, similar to the tree forming jutsu of the first hokage. The members are small and have a lot of muscles and most of them are bald headed, because they work under high temperatures.

Not too bad... but how about this instead of creation of metals: Slight manipulation of metals so as to fuse them and be able to more easily repair broken equipment.