Heat generation in bearings of self-driven rotary cutting tool was investigated to improve the bearing life. Three type of tests, cutting test by rotary tool, cutting test by fixed tool and loading test modeled on cutting, were conducted to clarify the heat generation. The results showed that the heat generation in the bearing was caused by the excessive preload resulted from the thermal expansion of the tool shaft. The adoption of angular contact ball bearings preloaded by spring, which was hardly influenced by thermal expansion of shaft, was effective to the improvement of bearing life of the tool.

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The part relies on the experience of the worker in the turning process is abundant. The tendency is in the processing of the center hole. The destruction of the center hole becomes a maximum credible accident. This paper advocates the safety standard concerning the center hole. It is a simulation concerning the center hole by using of experimental mechanics and computational dynamics together. This study is composed by the method of analyzing 5 pieces. The method is an isochromatic line, an isoclinic line by the photoelasticity method, two dimension finite element method, a tridimensionality finite element method, and method of caustics. In the photoelasticity method, it was done that the test specimen model by which the real machine parts straight side direction section dimensional standard was copied was done. The test specimen model dimensional standard used by the photoelasticity method was analyzed in two dimension finite element method. The model by which real machine parts was faithfully reproduced was analyzed in the tridimensionality finite element method. In method of caustics, an artificial crack was inserted in the test specimen model.

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