For example, if one treats the problem of metal contact, it becomes necessary to know statistically the various natures of the surface profile. In this paper, the theory of analysing surface profiles statistically is studied from a funamental point of view. At first, the relations generally existing between distribution function, density function, numbers of cutting, distributions of maximum points and minimum points, etc., of a surface profile, are given and then these relations are used to reveal the characteristics, especially, of the equi-inclination surface profiles with Gaussian distribution, for such profiles are obtained in most of surfaces produced in various machining operations. Next, it is proved that the above-mentioned equi-inclination surface profiles with Gaussian distribution can be replaced approximately by the fluctuations of independent slender columns. This result will be useful for analysing these surface profiles more minutely.

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It was proved, in the previous paper, that the equi-inclination surface profiles with Gaussian distribution can be replaced approximately by the fluctuations of independent slender columns.Therefore, such fluctuations are used, in this paper, for defining the distribution density functions of maximum points and minimum points of the surface profile, and for discussing the distribution of cut length or some other matters. Finally, the theoretical results so far obtained and described in the first and second reports, are compared with the experimental results obtained from the surfaces produced in various machining operations. And it is shown that the both results are in agreement fairly well.

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This paper describes an experimental research to find the effect of relief angle of cutting tools, as one of factors affecting on the roughness of machined surface. By orthogonal cutting of mild steel, we found that 6∼8 deg. relief angles were the most favourable from the stand point of roughness. The observation of tool with dividable tool leads us to the following conclusion : relief angle less than 6∼8 deg. causes the touch of machined material with flank of tool easily, and relief angle more than 6∼8 deg. causes instantaneous collapsing of tool point and vibration.

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This paper describes an experimental research to find the effect of the degree of tool finishing on the roughness of machined surface. By orthogonal cutting of mild steel we observed the relation between the roughness of cutting edge of tools finished with several kinds of method and the roughness of machined surfaces. This experiment reveals that the surface roughness is not affected by the roughness of cutting edge, if it is less than a certain limit, and that the increase of surface roughness eith roughness of cutting edge is attributed to the growth of built-up edge.

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In order to improve th ecutting performance of fine-grain abrasive stone, the authors investigated systematically a great many of fine-grain abrasive stones of various bond hardness, bond combining ratio, porosity and grain combining ratio, with the testing apparatus reported before, and obtained the following results. (1) It is not adequate to decide the cutting performance of abrasive stone only by the bond hardness (R_H), even in the same series of stones. (2) The stones with high bond hardness and small bond combining ratio are favorable. (3) The cutting performance of the stone with high porosity is excellent. (4) The grain combining ratio has not so mach influence to th ecutting performance as the porosity.

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In order to improve the cutting ability of fine-grain abrasive stone, the relation between the cutting mechanism in the superfinish and the working condition of superfinish has been investigated. Thus, the following results are obtained. As to the cutting motion in the superfinish, it is found that the frequency of stone oscillation has an upmost influence to the cutting mechanism among the various conditions of cutting motion, secondly the surface speed of work and amplitude of stone oscillation influence in same order to the cutting mechanism. When the superfinishing fluid (mixture of kerosene and oil) of higher viscosity is prefered, it is necessary to increase the cutting direction angle in order to get the most efficient condition of cutting performance. In addition, the characteristics of honing process may be classified into "cutting", "semicutting" and "mirror-finishing" according to the values of stone pressure and cutting direction angle.

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In pursuit of information concerning the performances of the preloaded ball bearing operating under fog lubrication at high speed, the coefficient of friction and the temperature rises of ball bearing and fog have been measured for angular contact type ball bearing of 40 mm bore with bakelite cage under the supply of spindle oil. The conclusions obtained from the experimental results are as follows. The fog lubrication widely reduces the hydrodynamic friction losses of the ball bearing as it may be lubricated with oil of minimum requirement securely and continuously. Though the higher rotational speed requires the more quantity of oil, about 3 cc/h of oil supply is sufficine at a dn-value of 800 000 in this case. The cooling effect of air is somewhat remarkable, but the effect of air for the temperature rise of bearing is less than the influence of oil under definite ratio of oil to air. Though the temperature rise and friction moment increase proportionally to the amount of preload under fog lubrication, when oil is supplied sufficiently, the increase of preload does not so much influence upon the temperature and friction. In the comparison with ordinary lubrications, the bearing temperature rise and coefficient of friction under fog lubrication are much smaller than that under oil lubrication, and the differences between fog and oil lubrications become larger according to the increase of rotating speed.

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An analytical solution by successive approximation including the effect of end of end leakage from the oil film of short journal bearings has been presented because of the importance of endwise flow in journal bearings of the short length commonly used. The analytical approximation is based upon the short-bearing approximation originally proposed by Michell and Cardullo and practically developed by DuBois and Ocvirk, and this analytical solution is obtained by using the solution of DuBois and Ocvirk as the fiirst approximate solution and then applying successive approximation method. In this paper pressure distribution, load capacity, locus of journal center and fluid-film friction are discussed, and these results may be applied best to bearings having a length-diameter ratio up to 0.6.

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As reported previously, the stability of air-lubricated bearing operating at high speed was much improved by setting a primary restrictor like a nozzle before the air-supplying hole against the position of the secondary restrictor through which air flows into the bearing clearance just after the air-supplying hole. When the capillary is applied as air-supplying hole, it becomes the primary nozzle and at the same time it possesses the activity of the secondary restriction just before the bearing clearance. In order to obtain a stable air-lubricated bearing, a number of capillary holes are located about the bearing equally spaced around its circumference, because these holes possess the activity which restrains probable vibration of shagt at high speed rotation. Then the air-lubricated bearings with capillary holes have been experimented by measuring frictional coefficient and quantity of air-flow and most suitable design of capillary holes is discussed. After all, the bearings running in very stable condition with extremely slight friction have been obtained.

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Several kinds of journal bearings, which are designed to have a multiplicity of convergent oil films in the bearing instead of the conventional journal bearings whch have single oil film in the bearing, are used as precision high speed bearings with very little clearance. Now, the multiple-film journal bearings having some fixed bearing surfaces of eccentric circular arcs are investigated theoretically to find the pressure distribution, the load capacity, the locus of center of shaft and the frictional resistance, because few theoretical investigations for the multiple-film bearings have been reported. So the designing factors to be determined in accordance with the particularity of the multiple-film journal bearings are described in this paper.

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Under a light load, the operating state of rolling bearing progresses into the fluid-film lubrication from the rolling contact between rolling element and raceway according to the increase of the rotating speed. A hydrodynamical Theory of fluid-film lubrication of cylindrical roller bearing was reported before by Buche. But the viscosity change due to pressure was not taken in his theory, regardless of the viscosity changes according to the change of oil film pressure actually. Then the fluid lubrication of cylindrical roller bearing has been investigated theoretically under the consideration of relationship between viscosity and pressure in this paper. The load capacity of the bearing increases greatly by the change of viscosity due to pressure, besides the fluid friction of the bearing calculated theoretically coincides well with the frictional resistance obtained experimentally.

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In this study some fundamental properties of skew gears with straight contact lines are investigated. The condition of meshing two ruled surfaces along a straight live is made clear. Therefore, four kinds of those gears are obtained from this condition. They are also classified as skew surface and developable surface. This report treats the skew surface gears. Their distribution parameter. basic differential invariants are obtained and interference of gearing is clarified.

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In this paper the use of the "Replacement method" for solving the under picking motion of the power loom is discussed. The picking stick and the side lever are replaced to the mechanical models which are transformed to the electric circuits by the concept of the "Mobility". Good agreement is obtained between the experimental and theoretical results, and it is shown that this method is more useful for determining the shuttle speed of the power loom than the others.

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A Standardizing box with a glass block in its mercury reservoir has been made for the purpose of preventing fluctuation of readings caused by the change of room temperature. The thermal dilatation of the mercury is compensated by the difference between the thermal dilatation of the steel vessel and that of the glass block. The precision of this box was much improved and the correction of measured values for the change of room temperature became unnecessary. Further, it is shown that the box is scarecely influenced by the heat due to the sources other than the room temperature, and the necessary bolume of the glass block with given thermal expansion coefficient can be easily determined by a simple formura.

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I introduced a method of determining tungsten carbide tool life for cutting of steel in the 1st report of this research, and again, I suggested a general method being applicable for all cutting tool, at the 32th Annual Meeting fo J.S.M.E., 1955. To determine the life of tungsten carbide tool for the cutting of cast iron under my suggestion, the results of analysis as to the behaviour of wear of tool are shown, with tangible process of determining the tool life in question.

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As a simple life test of high-speed steel, Brandsma's circular disk cutting test is prevailing, but it is not useful for tungsten carbide tool, because it has much experimental errors in this case. Therefore, we show a new methed of cutting test that is called "equi-diametric repetitive circular disk cutting test". It is applicable for determining the life of tungsten carbide tool, by flank wear, for cutting cast iron.

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We showed in a previous paper (4th report) that equi-diametric repetitive circular disk cutting test was applicable for determining life of tungsten carbide tool, by flank wear when cutting cast iron. But it is difficult for the life test life test by cratering when cutting steel. Therefore, we suggest a new method that is called "square type repetitive circular disk cutting test". It is applicable for determining life of tungsten carbide tool.

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