OT: I know, sorry bout this - fan blade ballancing

[J Miller]

My wife is a pizza delivery driver, and sometimes does home delivery for the pizza place's parent store. Today she did a delivery and the lady was moving. In her garage was a bunch of tools my wife scarfed and two fans. One was a newish plastic cheepo, the other was an ancient Hunter Zephair with big 15" stainless blades.

Zephair fan a.JPG

It actually works even though it's probably from the 1940s. Unfortunately the blades are a bit bent and look to be out of balance.
The bent I can fix, done that before, but how do you balance the blades? I don't mean how to add weight, that's the easy part, weld or put a screw in the light one(s), (notice the screws in the bottom two blades in the pic) but how do you rig the blade so it will show where the heavy side is?
The fans motor creates enough resistance to make doing this unreliable with the blade on the fan.

Any ideas?

Joe

[Hobie]

Do you actually see/have a problem when you run the fan?

[J Miller]

Do you actually see/have a problem when you run the fan?

Oh yes, it shakes and vibrates like crazy.

Joe

[TedH]

If you have a hobby shop nearby they may have a model airplane propeller balancer they would you use. You'd have to take the blade off, but it should work just like a prop.

[J Miller]

If you have a hobby shop nearby they may have a model airplane propeller balancer they would you use. You'd have to take the blade off, but it should work just like a prop.

Ted,
Thanks for the idea, I believe there is one close to me.

Joe

[Gun Smith]

First, Take a pencil or dowel and run the fan at it's slowest setting. Gently push the pencil into towards the blade through the guard. Each blade should just touch the pencil. Adjust (bend) the blades so they all just touch. You may find that's all that is necessary to rebalance the fan. Also the blade may be loose on the shaft. There should be a set screw on the blade sleeve that tightens the blade to the motor shaft. Unless the blades have been cut or otherwise damaged they shouldn't be out of balance.

[J Miller]

First, Take a pencil or dowel and run the fan at it's slowest setting. Gently push the pencil into towards the blade through the guard. Each blade should just touch the pencil. Adjust (bend) the blades so they all just touch. You may find that's all that is necessary to rebalance the fan. Also the blade may be loose on the shaft. There should be a set screw on the blade sleeve that tightens the blade to the motor shaft. Unless the blades have been cut or otherwise damaged they shouldn't be out of balance.

Gunsmith,
I can see the blade is bent by looking down on it from the top. However I will use the pencil suggestion to determine which ones are out of alignment.
And I'll check to make sure it's not loose on the shaft.
There are some nicks on a couple of the blades but they don't look too bad. However how bad do they have to look to cause trouble?

Joe

[horsesoldier03]

When I was in Iraq, I had a fan that was out of balance. I used 100 MPH Tape strategically placed on the blades to balance it out.

[.45colt]

Once You get it right these old fans are too cool . We have a big black Emerson from the '40's that came out of My Grandmothers house. 4 speed, gear driven and weighs about 25lbs. it really move some air.

[adirondakjack]

Blade has to be uniform otherwise it pushes air unevenly, acting the same as a weight-based unbalanced condition. The motor bushings (I doubt they are real bearings) also need to run very free and yet not sloppy. if the bushings are worn and the fan is bent at all it will set up harmonics that drive ya nuts. Visually straighten the blades, oil the bushings so they turn free, and see what ya got. Could be something as subtle as a little tweak on the angle of one blade will damp out the vibration (or make it much worse).

[mescalero1]

Joe,
Do you have a stobe light or timing light?

[J Miller]

I did what Gun Smith said and marked the out of alignment blade. Only one was way out, maybe another a little out. Bent it a bit and that made a noticeable improvement.

Then I started having trouble with the plug. After getting the blade as close as I can with it on the fan I turned it off and pulled the plug from the wall. KAZORCHE!!!!!!! Big ball of fire and smoke as the wires in the plug shorted. Got my attention, and startled my wife a bit. Now I gotta take the plug apart to see what happened and clean the soot off the wall outlet.

What I'm going to do is take the blade off the fan and set it on a flat surface, then adjust all of them to match.
I've done that before with a car fan and it worked.

Then oil and lube and then we'll recheck the balance end of it.

I love these old fans. They put more air out on low than the new plastic fans do on high. I've got an old Emerson from the 19teens that's been in the family for over 40 years. I need a part for it and the motor windings repaired. Then I could fix it. Don't know where to go to get the motor fixed though.

M1,
Yes I have an automotive timing light, but it's 12v DC only.
No strobes.

Joe

[Blaine]

Joe, fear not, we are all fans of yours and we know good and well you can blow hard.

[m.wun]

Remove the blade and hang from a string at the center and see how it hangs...

[J Miller]

Remove the blade and hang from a string at the center and see how it hangs...

m.wun,
I have the cage off the fan, and the set screw out of the fan hub. It's on there very tight. Letting it set with oil tonight, will see what I can do to get it off tomorrow.
I'll try hanging it by a string. Should work.

I've straightened the fan blade pretty much on the fan, but it is very out of balance. I've had other fans with blades bent worse than this that did not vibrate at all. This one bounces and shakes something horrible. So it's gotta be balanced some how.

Joe

[Hillbilly]

those open cage mega fans bring back some memories.

My grandparents had a few of those with the oscilating contraption on them. I had a cousin who was "one of those kids" who you just could not tell anything to.

He bled like crazy for a couple of hours... and how he did not loose a finger I still dont know.

Good luck. I dont know who rewinds those old fractional horsepower motors... but I will see what I can dig up.