My motor did not have any threads, so two people with large screw drivers or homemade contraption with some C-clamps should do the trick.
As for the rpm, you are looking at least 400 rpm, maybe higher. It depends on what voltage you want to charge at. 12v will require some well sized blades (less than 4 ft) and at least 15mph winds. If you just want to have some fun, I personally have charged some sets of AA batteries in packs of 2 ,3, or 4, which you then can later rearrange into a 12v string to power a laptop or what ever. This would obviously be your cheapest route.
Gearing it up will be tricky and require a larger diameter than you may want (bigger = less control in high winds).