[TheForge] Weather vanes/Wind Sculptures

[Dave Brown]

At 07:28 06/30/04, you wrote:

>Good Moring Guys/Gals,
>
><snip>
>Anyone have any hot tips on designs that would allow a fairly heavy wind 
>sculpture to spin freely? I have some ideas on how to adapt a typical 
>weathervane system, but with a sculpture of any vertical height I am 
>concerned about maintaining axial position as well as point loading for 
>free spinning.

Ray,

Francis Whitaker, in his Blacksmiths Cookbook, talks about using the 
bearings and shaft of a bicycle pedal for the pivot.  Pro:  they do spin 
nice.  Con:  Need for periodic lubrication to insure rust free operation, 
using grease may be problematic for winter temperatures.  Would need 
modification to the outer sleeve, as the manufactured sleeve may be too 
thin for practical use with heavy pieces.

A more traditional and mostly maintenance free approach is to use a 
spindle, tube, and ONE ball bearing.  The central shaft for the vane can be 
any size and thickness of tubing or pipe.  You need ONE ball bearing, 
slightly smaller in diameter than the I.D. of the tube.  The tube needs to 
be capped.  The support standard for the vane can be of smaller, equal, or 
larger diameter than the aforementioned tube.  If equal or larger it must 
have an extension added that is slightly smaller then the I.D. of the 
tube.  The top of the extension should be flat, not concave and not convex.

Put the ball bearing inside the tube and slip the tube over the 
standard/extension.  The ball bearing will provide two minimal contact 
points between the tube cap and the standard's extension.

The length of all these parts will depend on where the center of gravity 
(vertically) is.  The vane itself has two other requirements:  1)  that it 
be horizontally balanced at the pivot point, and 2)  that there is a 
greater sail/surface area at the rear than there is at the front 
point.  This is so the pointer/arrow will always point INTO the wind.

When the movie The Patriot (Mel Gibson) first hit the theaters I had to go 
see it.  First thing I noticed in the opening panorama of "Boston Harbor" 
was that the weather vane that was central to the scene was pointed in the 
wrong direction.  It was pointing in the direction the smoke, therefore 
wind, was moving instead of pointing into the wind.  If you ever get to see 
this movie (vhs, dvd, etc) keep an eye out for this.

Hope this helps.  The way I wrote it may be clear as mud, but hopefully it 
covers the ground.

Dave Brown
Heritage Smithing
Green Bay, WI
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