Based on this question over in RPG, I'm trying to figure out how long it took to forge a sword in the Medieval/Renaissance smith to make swords. I am recalling a figure of about 9-12 months per sword, some other references indicate that Katanas would be made quicker. My google-fu is bringing up tons on the individual steps "hammer until it's the right shape", "grind until sharp", etc. but no real estimates of how long these steps individually take or how long the whole process is.
Wikipedia's page on Japanese swordsmithing provides some information on the time frames involved in the manufacture of good quality blades:
The page also contends that the production of steel from iron would take four or five workers at least a week. It also goes on to mention that, depending on the quality of the sword, the polisher might take weeks to get things done just right:
Assuming that the steel is already available, I think that it might be safe to extrapolate that a cheap but functional Japanese sword could have been made in a few days, a good sword in a couple of weeks or more, and a great sword in a month or more.
I have friends that forge knives and swords. Assuming you already have your steel stock, a couple days will be sufficient. Maybe less than one day if you work hard at it.
This will vary by smith and by sword type. An apprentice might take a week or more.