A brief description is given of an interferometric method for the direct evaluation of line standards in terms of wave-length of light, and its application to the practical measuring instrument for precision scales up to one meter.
In order to transfer the interval of the lines to be measured to the mechanical displacement of a reflecting mirror of interferometer by the application of Eppenstein's method, a photo-electric microscope is tested experimentally and the Eppenstein's principle is analysed theoretically. The characteristic of interferometers which have the right angle prisms or corner-cube prisms, is examined analytically in order to estimate the measuring accuracy of the mechanical displacement by the method of fringe counting.
The accuracy of the practical instrument is 0.05μ in the length of 1 meter.

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Using a new type cammera, we studied on the dynamical characteristics of the high speed fine turning which has sliding bearings. In the present research, the effects of the clearance and oil pressure were considered.

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Following up our 8th report on the high speed fine lathes, we studied on the effect of the cutting heat.

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The characteristics in wear of grinding wheels are investigated over an ordinary range of grinding conditions. Further, the size distribution of abrasive grains worn from a grinding wheel is measured. Experimental results reveal the rapid increase of wear as the grinding condition is brought severe. The size distribution, however, does not change remarkably throughout the experiments.
The effect of the grinding condition on wear is discussed in terms of the life of an active grain. The discussion leads to the conclusion that the life of a grain involves only a parameter, that is, the grain depth of cut which varies with the work speed and the vertical feed.

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An expression for the wear rate of grinding wheel is developed from a consideration of the fracture behavior of brittle materials, whose fracturing probability is believed to show the strong time and stress dependence. It is shown that the wear rate of grinding wheels is to be expressed as the single exponential function of the grinding velocity and as the double exponential function of the grinding force. Experimental results confirm the theoretical interpretation.

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In succession to the 3 rd report the effect of hot machining by electric current is studied. In this paper following five materials are machined by this method, they are Cr-Mo steel 13% Cr stainless steel 18-8 stainless steel special heet-resisting steel and high manganese steel.
The conclusions derived from these experiments on the effect of hot machining by electric current (including the 3rd report's) are as follows.
(1) The electric resistance between cutting tool and workpiece is inversely proportional to the cutting area approximately and scarcely influenced by cutting speed.
(2) The mean temperature rise at the region between shear plane and rake surface by this method is mainly governed by Joule's heat and the heating efficiency η is estimated 1/3 to 1/4 when this method is applied.
(3) Built-up-edge can be easily eliminated by this method.
(4) The ratio of force reduction in machining by this method is approximately proportional to the mean temperature rise at the region between shear plane and rake surface (the formula of the mean temperature rise is presented in the 3 rd report).
(5) The force reduction accompanies increase of shear angle φ, decrease of friction angle β, increase of φ+β-α and decrease of shear stress ratio τ_c/τ_s, generally, so high temperature rise at the rake face is expected when this method is applied.
(6) The longer tool life is expectable by this method.
Summarizing the experimental results, it can be concluded that this new method of hot machining is useful in the field of metal cutting.

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[in Japanese]

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