I can think of about thirty medieval-like weapons that can be instantly craftable. That means, if it means anything, that there is about five thousand craftable items that could serve the combat purpose in general, and stay durable for what it's worth. The grim truth is, really, the crafting system must be overhauled subsequently - with generalization of tools that are used in the creating/crafting process. So to guess, if I was to find a hacksaw and a wrench to comply with my hammer, and picked up a pipe or two along with a chain only to combine them with a steel frame, I could make a bunch of stuff. Let's just say I was to create a brutal, three-headed flail. All the components have their own damage ratios - so how does one combine 'em and not just assume they're coded in? So I grab a piece of wood for the handle, cut the frame into pieces, grab a screwdriver and punch some holes in it with the hammer, push the metal into the wooden stick, cut the chain into three pieces and make three levers out of the remaining steel frame lefties, make the pipes deadly-edged with the hacksaw and wrap it all up with some wrenching skills. That's a deadly tool, but how does one determine its damage? Say, a short chain with a lump of steel at the end further reinforced with a pipe makes 22+ bashing dmg, and some piercing added too. But if your blow is delivered three times, or maybe only two - if you have the skill to wield the bastard - what would be the outcome? And that sole weapon can have a dozen of modifications, but there is no in-game routine to help and determine the damage of freely-created tools-o-war.
It's a b*tch to be asked such a question - but if I was to make, for example, simple darts to help defeating some enemies and use materials that abound, how would the game tell the difference between 'em, and how would it calculate such?