Globe...Help

[Jim Arnold]

I received a request to make an Earth globe, all out of wood. No political separations, just the land masses themselves on the 'round' Earth.

Any suggestions on making a 2' diameter wooden ball?

Thanks everyone,

Jim

[AlArchie]

Jim, I think it's time for a glue-up and a lathe! That's a pretty big ball, but a lathe with a 12" throw should come pretty close. Ot two half spheres on a bowl lathe.

Al

[mpounders]

I saw a jig for a router in a Fine Woodworking book that was used to make a huge ball....I believe it rounded everything, except two small end-points where it was mounted in the jig. I think it was some type of gimbeled type arrangement, mounted top and bottom, that would allow the router to swing completely around the blank, and then you just moved the router up and down in it's mounting. I will see if I can find the title and isbn number of the book or scan some pictures maybe.

[Claude]

If you don't have a lathe, it's possible to glue up a bunch of triangles of wood (Google icosahedron - but with more sides). For example, you could make a sphere just slightly under two feet in diameter by making equilateral triangles with side length of 3.14 inches. Assume you used 1 inch thick wood, you'd need to taper the edges exactly 82.5 degrees on a table saw so that they'd form a sphere as you glued them together. Once you have the triangles cut out, glue them together, then use a portable belt sander to sand the "ridges" down to a smooth even-surfaced sphere. How many triangles? Well, the surface area of a two foot diameter sphere is roughly 1810 square inches, and each triangle is roughly 4.25 square inches, so that's roughly 426 triangles...

Claude
<edit> the reason for using 1 inch thick wood, is that after you sand carefully, the remaining wood will be about 3/4 inch thick at the joints, so that should still be enough surface area for good strength. </edit>

[Dicky]

A wood lathe that permits outboard turning would probably do the trick.

[Jim Arnold]

Thanks for the help you guys! Great ideas.

Claude, thanks for the calculations! That reminds me of the Waterford Crystal Ball they drop in Times Square for ringing in the New Year.

This place is the best.

Jim

[A_Swope]

I know you can buy eggs so you might be able to buy spheres

[Jim Arnold]

Just off the top of my head, I like the idea of turning two bowls. Then I could just do some beading or strip type deal to cover the glue up and call it the Equator making it appear almost seamless and go from there.

I'm getting a nice commission for a chess set for the library and they threw the globe idea at me at the last second. I almost said no right away, but managed to keep my mouth shut long enough to tell them I would consult the experts and see what I could come up with.

I'm glad I did!
Thanks Again Everybody,

Jim

If I end up getting the commission, I'll be sure to post progress pics.

[LMiller]

Originally Posted by Jim Arnold

I'm getting a nice commission for a chess set for the library

We will want to see pictures of the chess set too!!!

[hwallen48]

Can't wait to see pictures when your done!!