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.
Step 1: The Tear Down
You wont need too much stuff for this build.
- circular saw
- ceiling fan blades
- solar power system 12 or 24volts.
- DC speed controller is optional
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.
Step 2: Noisy Gears
As I said at the start, one of the main disadvantages of using a saw over a treadmill motor is the amount of noise the gears produce. Removing the gear box cover and filling the gears up with grease did help shut it up significantly, All so I found that placing a thin washer on the shaft helped the gears mesh a little better and also helped a lot.
Step 3: Making Out the Saw Blade.
Its a good idea to use a paper template to make out where the blades need to fit and if you not sure how to do this go back to my first ceiling fan instructable as it is covered in depth. You need to get the fan blades in the correct position or it will wobbly and vibrate, producing noise and make the fan use more power.
I simply glued the template on the saw blade and center punched three hole centers. Tek screws where used to hold the blades on and then the last three screws were fasten to the saw blade to finish of the fan.
Step 4: More Modifcations and Fitting the Fan
It was about now that I found that the part of the saws housing was going to be in the way of the fan. As it was broken anyway, part of it was easy to snap off, the rest was cut off with a jig saw. The "saw blade fan" was then fitted and I could try it out for the first time. The trigger was cable tied down and the lead connected to a 24 volt battery bank.
I found the energy consumption quite a bit lower than I expected, Just over 1amp at 12 volts and around 1.7 amps 24 volts so around 12 and 40 watts respectively. It also moves a far amount of air, so apart from the horrible noise from the gears it works very well.
I probably should say something for any one attempting the Darwin awards this year, Don't plug this in to the mains power! its running on 24 volts!
Step 5: Installation.
The fan was installed with a cheap speed controller from ebay, which is very easy to wire up 2 wires to the motor and a + and - to the battery bank. The hardware from an old ceiling fan was used to hang the saw fan from the roof, it all works well apart from the noise. The residents were very happy as it gets very hot and sticky in the bedroom, and as he said, when I'm asleep I can see it or hear it anyway.
I said I would keep an eye out (pun intended) for a more suitable, quiet motor and make another one and maybe move the saw fan to the shed.