Stranded Deep

Quickest and easiest way of getting this is to collect 40 rocks by either finding them strewn around an island or finding some ingots. These require a pickaxe to break them down.

Go to your build menu and from the crafting section choose stone tool (Its the top option). It only requires one rock to craft. Rinse and repeat another 40 times.

I got this when preparing for boss fights. Apparently crude spears count as tools, which is super fortunate since all you need is a stick to make them.