# Forum Home Renovation Metalwork & Welding  My latest challenge

## PlatypusGardens

That time of the week again. 
CRAAAAAZY PROOOOOOJECT TIIIIIIIIIIIME!   
Gotta build a stand for this HUUGE radiator fan, and make it turn.
Possibly radiator fan from an old Cat grader or loader.
Very heavy.     
It's not going to be like a windmill or anything like that.
Probably sitting with the lower blade about 400mm off the ground at the most. 
So, first attempt at making it spin is.... 
20mm shaft on 3 bearings.     
Was thinking of putting this double bearing setup closest to the fan and the single one about 100mm back.    
Have made a round plate (8mm) and attached to shaft, which will bolt on to the fan, using the existing holes.      
I don't know how much the fan weighs.....if I was to hazard a guess....over 50kg...surely. 
Hard to tell..it's pretty easy to deadlift it as it's not awkward to pick up, as such... 
Those bearings and the shaft should be strong enough..,,surely?   :Unsure:  
The guy I'm making it for just wants it "on a stand" in the corner of the yard, and for it to be able to spin "a bit" 
More of a conversation piece than a windmill.     :Smilie:

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## OBBob

did you meet said 'guy' at the scrap yard?

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## PlatypusGardens

> did you meet said 'guy' at the scrap yard?

  no they bought a couple of things from me at the markets a while back. 
When he asked if I could build a stand for a large fan, I didn't quite picture this haha

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## notvery

attach some gearing and a belt to a gerbil wheel...

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## OBBob

Find an engine ...

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## PlatypusGardens

Thanks guys, where would I be without you? 
Oh, that's right.....in the shed getting the job done.  
So....I got it all set up and after some struggling and lots of heavy breathing I got the fan on to the plate and it spins bewdifully. 
I took a few videos of it but you'll have to make do with some crappy screenshots of said videos.   
I had to set it up pretty far off the bearing to clear the bench but there's no sign of the shaft bending even at this offset so everything should work just fine. 
Phew. 
I can relax now

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## Uncle Bob

If you spin it when picking it up it will feel lighter  :Wink:

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## phild01

> If you spin it when picking it up it will feel lighter

  ...even if awkward!

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## PlatypusGardens

The gyroscopic effect will be a killer

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## ringtail

That's huge PG. The fan boss looks like 6 mm plate ? Looking again, more like 8 mm

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## Marc

The shaft bending? No chance. 
You could make the stand in the shape of a windmill tower, sort of narrow pyramid, and on the face or the side make a silhouette of Don Quixote on a horse with his lance ...  :Smilie:

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## Uncle Bob

> The gyroscopic effect will be a killer

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## notvery

> The shaft bending? No chance. 
> You could make the stand in the shape of a windmill tower, sort of narrow pyramid, and on the face or the side make a silhouette of Don Quixote on a horse with his lance ...

  Just got strange looks when i laughed and used the voice that isn't only in my head while reading that.

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## Marc

The voice in your head?

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## PlatypusGardens

I weighed it earlier. 
50KG on the dot.

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## OBBob

Not posting it then?

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## Bros

You're up to the challenge.

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## PlatypusGardens

For the stand he wants something similar to this one, which could be tricky     :Unsure:  
It'll probably work though, but the legs have to be pretty wide apart.
And the fan centered between the 3 points. 
Hmm. 
I have some 50mm pipe for that.   :Smilie:

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## PlatypusGardens

Attaching the shaft to the plate, I drilled a hole in the plate, punched the shaft in, welded the front.
On the back I put the inner ring from a bearing, welded it to the plate and the shaft.
Should be plenty I reckon.   :Smilie:

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## commodorenut

Are you going to have a go at welding up that crack?  That's obviously why it was removed - the vibration would have been immense.

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## SilentButDeadly

I'm picturing the next cyclone to hit Mackay....and an unrestrained spinning fan.

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## PlatypusGardens

> Are you going to have a go at welding up that crack?  That's obviously why it was removed - the vibration would have been immense.

  Nah he's not bothered about that.
It has two cracks on the other side too, and what looks like weights added to at least one of the fins to try and balance it maybe. 
And yes, imagine this thing spinning at full speed....

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## PlatypusGardens

> I'm picturing the next cyclone to hit Mackay....and an unrestrained spinning fan.

  Might make the news!  
One of the landscape yards here has an old ceiling fan, standard 3-blade type, mounted horizontally on a tall windmill stand.
Man that thing gets going when it's windy!

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## Fory59

Hi PlatypusGardens, the 20mm shaft will bend over time holding 50kg unless the hub has an offset no further than 30mm from the edge of the bearing (noted setup was for bench clearance testing). I come from the old school and we used to build Fans for the HVAC industry back when they would pay for quality. I do realise that this is a decorative item and won't be powered so there is no strain on the shaft just static weight. You're right regarding the position of the blade in regards to the stand legs and the centre of gravity. The weights on a blade would have been to balance it as per your thoughts. We used to tack them on and then run the fan flat out and adjust accordingly. I will admit you never stood in the line of the arc of the blades as the walls and roof were perforated with badly tack welded weights. Oh the days before OH & S. Just hope small child doesn't attempt to stop the blade if the wind gets hold of it.... the inertia from 50kg rotating takes some stopping.

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## PlatypusGardens

Fory, thanks for your input, much appreciated! 
I intend to set this up so that the double bearing is right up against the mounting plate. 
Would it be better to have the mounting plate I made at the front of the fan so the double bearing collar is actually in the center of the fan bore, or would it be ok to have it "at the back" as I had it there for testing, but with no offset? 
cheers.   :Smilie:

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## PlatypusGardens

Bearing setup sorted

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## PlatypusGardens

:Woot:    
Gave the tube bender a workout... 
50mm toob      
The bearing setup bolts on to a plate welded to the stand.      
I love it
I wanna keep it...   :Biggrin:

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## SilentButDeadly

Flash!  How are you retaining the fan shaft in the carrier?  It could do with a prettied up cover to the bearings too...got any bore casing?

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## PlatypusGardens

That shaft aint going nowhere.
i Had to hammer it in to the bearings it's that snug a fit. 
I'll see what ol mate wants to do, but I have a feeling he wants the shaft and bearings exposed for that "bare mechanical look.
Probably trim the end of the shaft off though

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## PlatypusGardens

And...."is it sturdy?" I hear you ask. 
To tip it in either direction, you have to lift the leg more than 400mm off the ground and given the weight of the fan, that requires some effort even when grabbing it at the tip of the blade at top dead center... 
(this was one of my biggest concerns but no dramas there)

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## SilentButDeadly

> Probably trim the end of the shaft off though

  Nah!  Put a handle on it instead!!

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## PlatypusGardens

:Rolleyes:

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## PlatypusGardens

Ol Mate came by yesterday to inspect.
Very happy.   :2thumbsup:   
It acually turns by itself when the wind is right.
We were standing there talking and it started spinning.
Awesome.                 
The bending worked pretty well but with a few dings here and there but to be expected.   
I'll be sad to see this go, but another mate dropped by to check it out and reckons he knows someone who works for Caterpillar so hey.....I might be getting hold of something similar for myself. 
If I do I'll set it up as a proper turning windmill with a tail fin..... 
.....maybe    :Wink:

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## notvery

Attach a grinding wheel off the back and go off grid...well it's a start

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## Fory59

> Fory, thanks for your input, much appreciated! 
> I intend to set this up so that the double bearing is right up against the mounting plate. 
> Would it be better to have the mounting plate I made at the front of the fan so the double bearing collar is actually in the center of the fan bore, or would it be ok to have it "at the back" as I had it there for testing, but with no offset? 
> cheers.

   Hi PlatypusGardens,
Looks like you have it all sorted. The bearing mounted behind the plate is sufficient to take the cantilevered weight off the shaft. Looks great!

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## PlatypusGardens

Yeh having the plate at the front of the fan was more visually pleasing as well, covering up the hole in the center. 
Once the bolt heads get a bit of patina on them it should look even better

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## Bros

Now you want to paint a spiral on the fan and the dogs will be driven crazy.

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## Moondog55

But make the spiral in retro-reflective tape and shine a small spotlite at it

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