On Tue, 29 Aug 2006 19:07:20 GMT, "George E. Cawthon"
wrote:

mm wrote:
Just a story. No questions, although some of you might still have
answers.

I have a fan with a little 3 1/2" x 3 1/2" flat metal base that I keep
mounted on the window sill over my bed. It's the only fan that will
fit, and I have to nail one of the corners into the wood sill to keep
myself or the curtains from knocking it over. It has one blade and as
protection, only a couple wires so that it's easy to stick one's
fingers in it. But the motor isn't powerful enough to hurt someone
much, I think**. It's 50 years old or more and I think it was once
riveted to a factory machine and used to blow air on the operator.

It has to be oiled every 2 weeks to 2 months. I'm guessing it only
last 2 weeks when I didn't get the oil in the right place. I don't
know why it lasts 2 months sometimes.

I've let it get unoiled several times to the point where, in the
middle of the night, it stops spinning and gets very hot. But it
always works fine again after I oil it.

One time I couldn't find my 30 weight oil, and I used 10W-30. The
same night or soon after it stopped spinning in the middle of the
night and smelled bad, although I couldn't tell if that was the
windings or the oil burning.

I oiled it again, but it never got up to more than half speed, and was
very hot after about 10 minutes. I kept wondering if it was the
10W-30 somehow.

Finally noticed that the blade had come loose from the shaft. It was
like this when I got it, (**which is why it never hurt to put my
fingers in there,) and it would make a noise (that everyone at work
laughed at, and they bought me another fan, which I didn't want!)
until after about 30 seconds the blade was spinning as fast as the
armature. But this time, it never got up to speed and it didn't make
any noise, and it got very hot. I thought it was ruined, but now I
think the fan wasn't blowing enough air through the motor case vents.

I had glued the shaft once, and now I reglued it, and now it spins
fast and doesn't overheat. It's back to normal!

Hope this wasn't boring.

I can't see the point of the story and would be
terribly embarrassed to write something that
illustrates such a lack of knowledge. Sorry if
this is a bit harsh.

First: the problem isn't lack of oil,

Did I say, "The problem is lack of oil"? I said I had to oil it
frequently and when I did, it was back to normal. I'm not some
stupid or lying politician etc. who attempts to summarize things or
flee from a question, and in doing so makes statements that are hard
to prove, or in some cases false.

I just give the facts. Once one gets in the habit of doing that, it's
fairly easy.

I would be embarrassed to imply someone said something he didn't when
criticizing him. Sorry if this is a bit harsh.

the problem
with any 50 year old fan is usually one of the
composite thrust washers disintegrates leaving a
tar like substance that binds the shaft.

Except to replace the cord, I don't think I've ever taken the fan
apart. I probably would have seen and cleaneed at least one end of
the shaft if it had been dirty then, but that was a long time ago
anyhow. I don't know if there is anything on the shaft or not.

But I don't think it has oil-impregnated bearings, and iiuc, if it
doesn't and they are metal bearings, they have to be oiled
periodically.

A little
oil helps dissolve the substance but doesn't get
rid of it so it binds after a short period.

It lasts between 2 weeks and 2 months. Oiling again is a spall price
to pay for having the right fan.

Since oil solves the problem, I think it would probably be fair to say
the problem is lack of oil. But I didn't say that.

The
solution is to take the motor apart, clean the
shaft and the bearing surface thoroughly, and
replace any composite washers with brass,
stainless steel, or nylon washers. Then you oil
it once every year or two at most.

I can't get at the blade end of the shaft without removing the
"screen" and the blade. The screw that holds the blade on is already
damaged, flared at the slot. I don't want to go looking for trouble.

I would really like to see if there is substance from the thrust
washers, etc. on the shaft, but I have loads of other things to work
on , and I've learned not to go looking for trouble.

Second: fan blades are never glued to the shaft,

Mine are**. For the last 14 years.

they fit by compression or by a screw from the fan
hub to the shaft.

That's how the collar fits on the shaft, but not how the blade fits on
the collar. There is a collar and a set screw, but the blade is no
longer tightly crimped to the collar. My experience tells me that if
I disassembled the thing (which I don't want to do), if I tried to
recrimp it with a hammer and a dull chisel or a punch, the metal would
be too soft to stay that way for long.

**Well, my blades are glued to the collar which is attached to the
shaft with a set screw.


There is no reason for me not to have used glue. Glue is used for
loads of things, but even if it weren't, it works here. The tiles are
glued to the space shuttle, and my fan doesn't face the risks of
re-entry.

Third: Never heard of a one bladed fan; it would
be terribly unbalanced. Maybe the OP means a two
bladed fan (two parts sticking out on opposite
sides of the shaft).

Yes, I meant a two-bladed fan like you say. At the time of posting, I
thought my language was pretty clear with the fewest words, to convey
how simple the fan is. If I said two blades, I was afraid someone
would think two long blades with four ends. Thanks for clarifying
this.

Fourth: There are all kinds of small fans from
1-1/2." x 1-1/2" to 4-1/2" by 4-1/2" Many are DC
for use in computers and other electronic
equipment but many are also 120 V AC, and they
have more blades.

True.