Revised 02/09/2020

Several years after retiring as a math/computer science professor, a bother and cousin inspired me to get a lathe and try turning wood. After my wood turners club had a couple meetings with demos of turning 3 sided bowls (or 3 cornered bowls) and attempting to turn some, I became enthralled with the geometry of those bowls. After doing an analytical analysis, it became apparent that the geometry involved nothing that wasn't normally taught in a high school geometry course. So I wrote a page with the results of the study attempting to write it at a level that could be understood by a wood turners who after several years had forgotten the material in their geometry course. But it occurred to me that the analysis might be of interest to someone interested in geometry without any background in wood turning. I decided they would need to know what a 3 cornered bowl was and have a little idea about how one might be able to turn one.

- Some images of 3 sided bowls What is a 3 sided bowl?
- Turning a 3 sided bowl How can one possibly turn a 3 sided bowl on a lathe designed to make circular objects?
- Mathematical analysis Can a simple mathematical analysis be helpful in planning 3 sided bowls?

The picture above is a top view of bowl on the left with an equilateral triangle drawn on its corners.

*Maintained By:* James Brink (brinkje@plu.edu).