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Monday, May 14, 2018

Fan Repair

Power tools at the ready. Didn't use the torch on this project.
We have a floor fan, i.e. a fan mounted on a pedestal that we got as a wedding present umpteen years ago. My wife drug it out the other day, probably something to do with the weather getting a little warmer, turned it on and it wouldn't go. Seems the bearings are gummed up. The fan will turn, but it takes more effort than the motor can deliver. This should be easy enough to fix. It's a simple electro-mechanical device put together with screws. I should be able to disassemble it, clean and oil and bearings and we should be as good as new. Hah. Foolish man. Three days later I finally completed this supposedly trivial task.

Front motor housing with stator

Disassembly goes well until I go to pull the knob that engages the oscillating mechanism. It looks like there is a Phillips head screw holding the knob on but no amount of force will convince it to turn. Fine, I'll drill out the screw head. That'll get the knob off and we'll worry about how to reattach it later. If I have a left-hand twist drill bit that would be better, as at some point the screw may give up and the drill, instead of cutting into the screw head will snag it and it will unscrew. Surprisingly I do have such a bit (where did that come from?), but it doesn't help. The bit cuts almost all the way through the screw head before it goes off center and destroys the knob. Well, we got the knob off, we can now proceed with the disassembly. But look: there was no screw. The screw head was simply a flare on the end of the shaft. We've seen things like this before on things made in China. They have made a copy of an American design, but they found a short cut that enabled them to use fewer pieces, but because they are making a copy, they make the copy look just like the original, including screw heads for screws that are no longer there.

Small parts. Left hand screw in jaws of Vise-Grips

The next hiccup is the screw holding the link to the oscillating crank. The screw head looks just like most of the other screws holding the motor together, but it won't come out. I end up using the left-hand twist drill bit on this one as well, but I still need to get the screw out of the hole. There is enough of the screw sticking out of the other end that I can grip it with Vise-Grips, but even with the head gone, it won't turn. Then I get the idea that maybe if I try tightening it a bit it will break free and then it will unscrew. Tightening it does break it free because it is a left hand thread!

Rear motor housing with oscillator, crank and the wrong screw

The rest of the motor comes apart easily. I clean and oil the bearings and start reassembly. Now I need to reattach the link to the oscillating crank. You might know where to find a left-hand thread screw of the correct size, but I sure don't, so I pick a likely looking sheet metal screw and use it. The arm is diecast so it goes in easily. But now I think that maybe I should do something to ensure that it won't unscrew, after all the people who originally built it went to the trouble to use a left hand screw here for that reason, and if this fan is going to run for another umpteen months, we don't want this screw backing out.

Gluing broken crank arm back together

So I pick up a center punch. I figure I could punch the side of the arm and it would distort the metal enough to solidly grip the screw and prevent it from ever turning. But when I hit the punch with a hammer, it cracks the arm in two right across the screw hole. Bah! Double bah. Triple humbug.

Oh well, time to break out the epoxy. Glue the end of the arm back on, along with the screw. Wrap some picture hanging wire around the arm to hold it together. As long as it doesn't get in any fights it should be fine.

The green wire has broken free

Green wire soldered back in place

One wire popped off of the switch and I soldered it back on. One of the feet has been coming off for years, a little silicon sealer secured that. I filed down the jagged end of the oscillator control. If I ever want to disengage it I can grip it with Vise-Grips.

This whole exercise makes me wonder which way is up. I don't imagine this fan cost more that $20 when it was new. Of course that was long ago enough that $20 was still real money. You can buy a similar item from Amazon or Ebay for about $30 now. I spent a couple hours working on this, triple that if you count all the time I spent looking for bits and pieces, so economically it doesn't make any sense, unless my time is worth nothing, which it apparently is. I mean who would hire someone who would spend hours trying to fix a cheap fan? But I am rather pleased that I got it running again, even though the oscillator control is not quite so easy to operate.

Update: Peter Grant has a related post.


Anonymous said...

You are amazing! My father would be proud of you!

Anonymous said...

*Laughing, maniacally* I am so glad to read of your troubles (please know that I am laughing with you!) It means that I'm not the only overly-rambunctious DIYer. We can be smug in the knowledge that we are conscientiously conserving resources and minimizing waste.
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The Institute said...

Great post.

1. The lesson of the Potemkin Screw is valuable. As technology and digitalization increase, the staples in our lives are being replaced by new iterations, and I've had the creeping feeling that sometimes these new innovations are mere hollow imitations of their predecessors, assuming the form but lacking much of the former significant substance. I remember during WWII when meatloaf was replaced by "Victory Loaf" on our dining table. And when decent politicians with good ideas were replaced by telegenic dudes in suits who were good at hurling insults. Thanks, technology.

2. Engaging in skilled tasks is good, and beneficial. It builds the brain. You spend a month studying math, reading, drawing, writing, or repairing complex mechanisms, and you can feel your brain working better. You exercise your body for a month, you'll find your body working better. That's why northern cultures, who were forced to plan ahead over the summer, and spent winters indoors studying and tinkering, developed more technologically than people who lived hand-to-mouth in sunny climes. In terms of cost, in most cases, you won't be able to compete economically with robots who are stamping out widgets at 100 pieces per minute. That's not why we do it.

Anonymous said...

P.S. Just found this appropriate cartoon on xkcd:
Cop Car