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I’m getting a teeny bit closer on my little CNC mill/lathe project and after test running the treadmill motor driven spindle wide open for a while to check the bearing preload, I found that the motor was heating up considerably since it had no cooling fan. I thought about mounting a fan blade on the rear shaft but figured it wouldn’t be enough at lower speeds. I had previously stripped down an old PC power supply to get its power socket for the motor hookup and thought hey, here’s a perfect little cooling fan motor as well!
I whipped up an aluminum bracket to mount the fan on the rear of the motor and in tests it easily kept the motor nice & cool. It’s a 12V motor and runs great with an old 12v 150 mah wall wart wired into the system relay.
I noticed that a lot of the air was wasted so I decided to make a duct to force all the air through the motor. I made v1.0 from stiff cardboard using a shareware cone generator program that outputs a .dxf. After playing CAD “paper dolls” and cutting out various templates, I wasn’t satisfied with the results and decided to try the old heat-shrink-the-2-liter-soda-bottle trick I used many times to make custom engine cowlings and canopies back in my model aircraft days. The P.E.T. plastic (polyethylene terephthalate) shrinks about 25-30% at approx. 400 deg f. and is amazingly tough stuff after shrinking.
I made a wood plug that duplicated the shape of the fan housing and the motor O.D. I turned the round end in the lathe, shaped the transition from round to square with the mill, a plane and coarse sandpaper. I then glued on a pair of blocks to make bumps to clear the brush boxes and then shrunk a bottle tightly around it. I slit it down one side to remove it from the plug and then installed it with a tyrap, a piece of aluminum 200 mph tape and a strip of filament tape. It fits perfectly! I’ll eventually put a screen on the inlet side to keep stray chips out of the works but am happy with how it came out for now.
I whipped up an aluminum bracket to mount the fan on the rear of the motor and in tests it easily kept the motor nice & cool. It’s a 12V motor and runs great with an old 12v 150 mah wall wart wired into the system relay.
I noticed that a lot of the air was wasted so I decided to make a duct to force all the air through the motor. I made v1.0 from stiff cardboard using a shareware cone generator program that outputs a .dxf. After playing CAD “paper dolls” and cutting out various templates, I wasn’t satisfied with the results and decided to try the old heat-shrink-the-2-liter-soda-bottle trick I used many times to make custom engine cowlings and canopies back in my model aircraft days. The P.E.T. plastic (polyethylene terephthalate) shrinks about 25-30% at approx. 400 deg f. and is amazingly tough stuff after shrinking.
I made a wood plug that duplicated the shape of the fan housing and the motor O.D. I turned the round end in the lathe, shaped the transition from round to square with the mill, a plane and coarse sandpaper. I then glued on a pair of blocks to make bumps to clear the brush boxes and then shrunk a bottle tightly around it. I slit it down one side to remove it from the plug and then installed it with a tyrap, a piece of aluminum 200 mph tape and a strip of filament tape. It fits perfectly! I’ll eventually put a screen on the inlet side to keep stray chips out of the works but am happy with how it came out for now.
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