Ok, well something is very wrong with crafting right now. I just made a Ranger with a crafting skill of 3 and a Warrior with a crafting skill of 0. No matter which order I tried to apply them in, the Ranger (with the crafting skill of 3) couldn't combine the knife and branch to make an arrow-shaft. Every time I tried the items simply swapped places in the inventory.

I then gave those materials to the Warrior (who has a crafting skill of 0) and he was able to make an arrow-shaft first try. What's with that?

I then had both of them try to make an explosive arrow by pairing the arrow-shaft to the explosive arrowhead, and neither could.