Herbivore island is the safest place to grind out metal, there's 6-7 nodes in top and you don't have to worry about anything unless you wack a bronto. If you're lucky enough to find an island server without a base there it's the perfect spot to build, If you do this be sure to put out a forge and UNLOCK it for community use! Don't pillar the whole island like an idiot... Looking at you "stoned construction"!!!