Jeff Burks turned up an interesting patent for a camp stool that seems genius, and yet I’ve never seen an example in the wild.
Nathaniel Johnson of New York was granted patent 32,698 on July 2, 1861, for using a curious metallic (or wooden) orb as the centerpiece of a folding camp stool. In essence, Johnson calls for using an iron orb that is pierced by three rods as the folding mechanism for the stool.
In and of itself, using a sphere isn’t an improvement. But what Johnson shows is that each of the three legs of the stool has a sympathetic spherical recess. This small detail allows the legs to close tighter without significantly reducing the strength of the legs.
It’s a pretty smart idea.
The challenge, of course, is in implementing it. I’ll grant that a machinist of average intelligence could create the orb with the three threaded posts. But creating the spherical recess in the legs would be a trick with off-the rack tooling. I don’t know of many drill bits that have a spherical cutting surface. Some router bits do. But then you’d have to follow that tricky operation by drilling a perfectly placed hole for the rod of the hardware.
I can visualize a drill bit that would cut the hole and sphere in one go, but that bit doesn’t exist (as far as I know).
So this one gets filed in the “cool, someday” folder.
This has inflamed my lust to build some more campaign stools from the leather and wood scraps in my basement. And to dream of perfect spheres.
— Christopher Schwarz