Ok I know what your thinking, it's a bit early for April fools day, or Ive come down with a bad case of redneck.
I made this for my own amusement, as I was asked if I could make a 24 volt ceiling fan for a resident of footrot flats. I said I was having trouble finding a treadmill motor and jokingly said I could make one out of a circular saw... he ran off and came back with a saw, me and my big mouth.
If you want to make a solar fan I suggest you have a look at my other instuctable , it will show you how to make a ceiling fan with a treadmill motor which is quiet and very efficient.
This fan runs on 24 volts but is quite noisy, not as efficient and looks something out of mad max, but you might like that.
Now why would I use a circular saw? Many AC tools have universal motors inside them, they are the motors with brushes inside. Universal motors will run happily on DC so of course if you reduce the voltage they will run slower. So you could use a number of different tools for this project, "router fan" was my next choice but I couldn't find one. You could also try an electric drill, sewing machine, angle grinder, even a vacuum cleaner motor.
You wont need too much stuff for this build.
After confirming that the saw did run, even though its quite noisy, I removed the guards and the blade. This is not hard to do only three or four screws , and I then removed the the retractable guard and spring.