In the early 90s I had read an article on constant diameter shapes. Like most people, I had thought that only a circle has a constant diameter, but actually the circle is the only shape with a constant
radius ; there is a whole (infinite) class of shapes with a constant diameter. One of the simplest is a triangle with round sides. A slight refinement is the same triangle with rounded corners as well. The diagram shows those two shapes. I thought I'd try it out in wood so I made a roller with a symmetric shape on one end, and an asymmetric shape on the other. Both ends are of a constant diameter, and the diameter is the same on both ends. They are connected by an axle that has a wavy shape, primarily because I thought it would be too hard to make a straight one. You wouldn't guess even by rolling the piece on a surface that the ends are constant diameter, but setting a flat object such as a book on it shows that the book stays the same level above the surface, just as if it was rolling on a round cylinder
like this.
| Material: | Padauk |
| Finish: | Wax |
| Size: | 3" x 1.675" dia |
| Done: | Feb 15, 1993 |
