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 forging of a Japanese blade typically took many days or weeks, and was considered a sacred art, traditionally accompanied by a large panoply of Shinto religious rituals. As with many complex endeavors, rather than a single craftsman, several artists were involved. There was a smith to forge the rough shape, often a second smith (apprentice) to fold the metal, a specialist polisher, and even a specialist for the edge itself. Often, there were sheath, hilt, and tsuba specialists as well.
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:
When the rough blade is completed, the swordsmith turns the blade over to a polisher called a togishi, whose job it is to refine the shape of a blade and improve its aesthetic value. The entire process takes considerable time, in some cases easily up to several weeks. Early polishers used three types of stone, whereas a modern polisher generally uses seven. The modern high level of polish was not normally done before around 1600, since greater emphasis was placed on function over form.
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.
In medieval Europe it took a standard blacksmith about a week to make a decent average steel longsword. If they were making something for their lord or king they would often spend as much as 6 months ensuring they had the ornate design perfect, but that's about it. Usually a sword would take about 1-2 months to finish, not because they were spending that long making a sword, but because they'd be making a dozen or more swords at the same time to better make use of their resources; there's a lot of waste when you're smelting metals.
If you did nothing else, working a full 12 hour day, you could probably make a decent sword in two days if you know what you're doing. This depends on the style of sword and the method you're using to make it, but generally most steel swords are made by hammer and grind, heating and folding, or the more advanced technique of splitting into vortices; plaiting and welding. The latter method puts a natural fuller into the blade and was the common technique from 6th century onwards in western Europe.
Swords were not made by a single person. A blacksmith would create the blank, with the help of his apprentices. Then a grinder would grind the blade then someone would fit the hilt etc. Hammering out the blank probably took the least time. Each trade required its own specialized tools, materials and knowledge. Having ready access to all the materials and to modern equipment/machinery makes the job much faster today. If you know what you are doing, have the necessary skills and are properly set up, you could probably turn out a fine sword in a few days (longer if it is elaborately decorated). Like all creative arts, it's the subtle details that make the difference between an ok product and a great product and those take time to learn.