You would need a forging station. Wouldn't be cheap, for sure. Then, you buy blanks of the different weapons you can build (katana/wakizashi, or maybe all bladed weapons).
The bigger or better the blade, the higher skill needed and the time it takes to make said blade.
Something like a katana would need a blank that cost a lot, takes like 6 months to make, and needs past the curve in everything, stat/skillwise.