copper and bearings

[mixergirl]

Hiya - my first post - usually I go to the local machine shop or metal merchants and just get stared at while I ask for materials and parts and services no one around here wants or needs and then get a 'what do ya want to go and do that for love'... anyway.
After a crash self taught course in coppersmithing I am approaching an impass with a wind sculpture I am working on. 3 hammered copper shapes (in the 300mm x 15mm x 600 - 900mm range weigh individually up to 20 kilos) are to be mounted on poles 3.5 to 4.5 metres in height. The client requires a weathervane type movement. I can design a simple sheath and collar system but I am wanting to supply a bearing movement that will be very sensitive to the wind and will be very long lasting. The shapes will have collars welded to the bottom that will slip over the tops of the poles - what sort of bearing system could I install within that? Anywhere in particular I could look for that kind of information.
Also - is anyone out there familiar with working copper sheet? I am managing but just - a few pointers would be fantastic as I am having trouble with multiple curving - convex and concave needing to match up with exactly the opposite.
thanks for any assistance.

[GaryR52]

Something like this, perhaps? http://bearingsdirect.com/products/

Gary

[oddist]

Could you post a small hand sketch (scanner required) of what you are trying to do?

That or send a round trip ticket. :D

[fused]

Another source with many outlets who ships stuff everywhere is Grainger (http://www.grainger.com/Grainger/wwg/start.shtml). If bearings don't work out for your project consider bushings, Grainger has oil impregnated bronze bushings which are very durable and suprisingly efficient and come in a wide variety of dimensions.

If possible, I recommend making your wind sculpture in a way that allows for bearings/bushings to be replaced at sometime in the future. My first large wind driven work had a bearing in the top that the supplier claimed "would last longer that the life of my work" considering my application. It failed and froze up after one year in the Texas environment.

[mixergirl]

Could you post a small hand sketch (scanner required) of what you are trying to do?

That or send a round trip ticket. :D
here is a small sketch - basic ball bearing on end of pole type thing.

[oddist]

Ok, my little mixer...nice concept...

I would say this needs radial bearings to take the "side" loads and a "thrust" bearing to take the vertical load.

There are bearings that do both these functions.

I will post some examples later today.

What is the outside diameter of the shaft (support post) and the inside diameter of the sleeve at the bottom of the rotating part?

Stuff like this I do for a living. (We could actually get into wind speed and the load it would impart on the bearings..)

----------------------
It's 9:30 here now...I've been searching the web for some good pictures of bearing assemblies that might work for you. The simplest thing that comes to mind that won't involve precision machining capabilities is to get a hold of a bearing assembly from the front wheel of a car. An auto junkyard should have plenty to chose from. These use tapered roller bearings that resist radial and thrust loads. Here is the best picture (http://www.bearingbuddy.com/spindle_seal.html) I could find that shows the components.

What you need is the axle spindle, the inner bearing cone, and the hub. The spindle would attach to your post and the sculpture to the hub. Wheel hubs already have bolts so attaching to them would be fairly easy. Cutting down the hub diameter might have to be done to make the assembly fit your piece. An outer shell of copper could be made to cover all this stuff so it would look decent.

I'll work up a sketch and attach it..

---------------
9:51...here's a sketch..Hope this helps...Good luck...

-------
12:10...Just looked back at the size and weight of your pieces...they're not as large as I thought and only up to maybe 50 lbs... For this you might be able to get away with the bearing assembly from a motorcycle or bicycle wheel.. Just cut off all the spokes and mount the shaft to the top of your pole and sculpture to where the spokes where attached (or viceversa).

Hope all this helps.

[sculptor]

If memory serves, JAZ had a thread going in here about a year ago addressing the same problem--------and a rather thorough investigation followed

here's the link (http://www.sculpture.net/community/showthread.php?t=884&highlight=bearing)

hope this helps
rod
sculptor (http://home.mindspring.com/~mandali/index.html)

[EJB]

If you follow the link, I posted a low tech method for a bearing mechanism. It's the last one on the thread. If that does not help, I'll take a round trip plane ticket as well and will bring extra bearings.

Just keep it simple. Good luck!

[mixergirl]

If you follow the link, I posted a low tech method for a bearing mechanism. It's the last one on the thread. If that does not help, I'll take a round trip plane ticket as well and will bring extra bearings.

Just keep it simple. Good luck!

Hiya EJB - I didn't see a link on your message?

[EJB]

Click on the link in the previous post by SCULPTOR.

[warren01]

Mixergirl said "Also - is anyone out there familiar with working copper sheet? I am managing but just - a few pointers would be fantastic as I am having trouble with multiple curving - convex and concave needing to match up with exactly the opposite.
thanks for any assistance."


Mixergirl,
First question is what thickness of sheet? Because with different thicknesses it is easier to stretch or shrink the sheet to make the various curves.

Usually if you want a convex surface you do that by stretching the copper by pounding into a concave form. The sides will come up and then you can shrink the sides to remove the little folds. This a little hard to explain and there are various books out there with pictures to explain it all. I feel that one of the better books forming by hammer method is.............. Even though the topic is Silversmithing you learn first on copper. Very good book on how to move metal with hammers and forms.

warren

[Bugs]

I have mucked about off and on for years with forming metals. I have been getting back into it recently, mainly for the wonderful patinas! I ran across this site recently. Unfortuanately, the artist is now deceased but what a guy and what a website! Chris Ray has a lot of great information on forming copper http://www.chrisray.com/page01.htm After looking through his site I was interested in finding/making tools for forming metal (that is half the fun-metal yards). Anyway you may all ready know a lot of this stuff, but the shaping ring idea is wonderful for quick bulbous forms. I personally use a lot of gold chasers pitch. I heat it with a torch (you could use a propane tank) and drop my metal pieces in it. Once it is cooled I then start to raise out forms. The pitch keeps things tied down so to speak while you pound away.

I think looking for developing tools in all the wrong places can be a lot of fun.

Great links for bearing mechanisms everyone!

Bugs :eek:

[mixergirl]

Cheers to everyone for the great information and links - I will post a photo of the finished piece in the coming months as there is still a ways to go.