In the second report, in succession to the first report, the author regarded the surface to be tested as a series of straight lines or curves of the P th degree, and measured its straightness by connecting these lines successively. In the present paper, he mentioned its theory, errors of measurement and experimental results, and examined whether it is of practical use. The results are as follows : (1) In case of measuring straightness of the smooth surfaces such as mirrors, fine measurements may be carried out, but in case of the rough surfaces such as scraper-finished ones, the errors of measurement must be taken in calculation. (2) In case of measuring straightness of the surfaces which are long and rough, it is unnecessary to increase number of dial gauge in the former method, but neccessary in the latter method. (3) Straightness of the surfaces can be examined minutely by increasing the value of P.

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By the methods treated in the first and second reports, we can measure the straightness of the surfaces correctly in case of the smooth ones such as mirrors, but in case of the rough surfaces such as scraper-finished ones, the errors of measurement must be taken in calculation. Accordingly, if these rough surfaces were fairly straightened, their straightness measured by these methods may be seriously affected by these errors, and as an extreme case, the practical values will be lost. In this report, the author has mentioned the new integrating method free from such defect, and applying this method to the case of the rough surfaces, made it clear from both theoritical and experimental points of view that fine measurement may be carried out in this case as well as in case of the smooth ones.

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The surface of a abrasive stone may be considered to have a dence distribution of abrasive grains over the surface, however, the area occupied by the grains is rather small and almost all is a space. In the method of superfinish, using such stone, a finely finished surface is obtained in a comparatively short time by giving complicated multi-motions between the abrasive stone and the work, moreover increasing the area of contact between them. Hitherto, the frequency of about 2000 〓/mn has been suited for superfinish, however, from the above consideration it was expected to have a better result at a higher frequency. The frequencies of 3000∼300000 〓/mn were used in this research and the good surface finish was obtained.

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Data are presented showing the performance of the "Coolant through the wheel" in the grinding field which means a practice of supplying the coolant through the structure of grinding wheel with the aid of centrifugal force developed by the wheel rotation and having a merit of cooling the grinding surface of work directly. Experiments cover how the grinding forces are influenced by the amount of coolant, depth of cut or grade of grinding wheel in the cases of "Coolant through the wheel" practice and ordinary practice. As the conclusion, it has been clarified that "Coolant through the wheel" practice takes effect preventing the loading of wheel and is more effective when the amount of coolant is few and the depth of cut is large.

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In many cases, the cutting performance of the fine-grain abrasive stone is presumed by testing the bond hardness, but frequently we found different cutting performances for the abrasive stones of same bond hardness. In oder to test the cutting performance of abrasive stone, a special testing apparatus with which stone wear, stock removal and cutting force can be mearsured was designed. Then the testing results of cutting performance obtained with above testing apparatus was compared to the results of superfinishing performance with same abrasive stone under the most suitable working conditions, and it was clarified that this testing apparatus is effectually avaiable to investigate the cutting performance of the fine-grain abrasive stone.

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The tool-edge temperature, consists of both temperatures due to plastic deformation on the shearzone and due to tool-chip interface friction, varies by the work condition, heating temperature, energy on the shear zone and tool-chip interface, fraction of the heat to the chip or the work piece and physical properties of the work piece. The author measured cutting force, chip ratio, contact length of the tool-chip interface and also the edge temperature for various work conditions and heating temperatures with 0.26% C carbon steel under orthogonal cutting conditions. More-over compared with both experimental and analytical results. These results may be as follows : - 1. The generated edge temperature would be lesser at elevated temperature than at the room temperature. 2. The edge temperature would have exponential relation with cutting area, cutting speed and depth of cut/feed., and exponent value would decrease according to an increase of the heating temperature.

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Results of experimental studies on a new-deviced thread rolling machine using a pair of rolling dies of eccentric roller type are described. (1) By a new thread rolling machine, the rolling dies were fixed slghtly eccentric on each axis of rolling dies, which was fixed at any desired distance during the rolling operation. (2) The outside of the rolling dies is circular form and not relived, so the accuracy and the durability of rolling dies are satisfactory compared with those of the thread rolling machine of hydraulic type. (3) The construction and the operation of the new thread rolling machine are very simple and so the full automatic operation could be realized very easily. (4) During the operation, the rolling pressure changes very gradually and the rolling forces are not unbalanced, so the rolling action is very smooth and not causes any accident. (5) Diameters of threads which can be rolled by this type of machine range from 2 mm to 16 mm and up to the length of 60 mm. (6) The work pieces were fed automatically to the rolling dies and the thread rolling could be completed in a few seconds, the work piece being made 5∼12 revolutions by thread rolling according to the diameter. (7) The accuracy of the rolled threads is so high as the grade JIS 1 st class. (8) By this machine, the threading action must be completed during about half revolution of the rolling dies, so the diameter of the rolling dies is comparatively large, say 140∼160 mm.

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For the six kinds of white metal bearing alloys, we have studied the hardness distributions of ingots after cast in metal moulds, and the wear-tests under very light loads and low velocities. The following conclusions are drawn : - (i) The hardness distributions of lead-base alloys were superior to those of tin-base, and their ranges of equal hardness were more broad. (ii) Under dry-condition, amounts of wear of WJ 3, on tin-base, and WJ 9, on lead-base, were largest. The velocity at which WJ 1 showed the maximum amounts of wear was highest and that of WJ 3 was lowest, and heavier the loads were, that stuated at the lower velocity at every alloys. (iii) Under wet-condition, amounts of wear increased almost neglegible slightly with load, and decreased with velocity in the same manner. Amounts of wear of mild steels which sliding on the alloys were nearly equal for each alloy.

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In this paper the author shows analytical study of cams applying the theory of gears, and points out the errors in the method for determining the least radius of the base circle by Alt, Furman and Flocke, and proposes new methods for determining the basic dimensions of various cams.

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Up to this time elliptical gears are not used widely, because of the difficulty in their production. In this research we tried to cut pseudo-elliptical gears which could be used in place of elliptical gears and be easily produced. Namely, we cut them employing a common hobbing machine and ordinary hobbs for spur gears, though a simple attachment installed with eccentric circular cams was laid on the hobbing machine. Also, the deviation of the pseudo-elliptical gears from the elliptical ones was calculated and then it was made clear that to what value the eccentricity of an elliptical gear could be raised without injuring the ability of replacement of the elliptical gear by the pseudo-elliptical one.

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