Abstract
In processing by lathe, the work is processed by experience of craftsman. Also center hole in processing by lathe, this tendency is untill today. If center hole is destructed, it is serious accident. Therefore, this study suggestes standard for safety. This study is formed four kind experimental method. This method is isochromatic line and isoclinic line by photoelasticity, finite element method. In the first, three dimensional model is transformed to two dimensional model. And, it is modeled two dimensional specimen. By this specimen, isochromatic line and isoclinic line by photoelasticity and caustic method is applied. And, finite element method is applied to shape of two dimensional specimen and three dimensional model.
