In order to clarify the nature of the noise of roller-chain driving and to find out the way for decreasing the noise level of the roller-chain driving, the authors have studied the impact noise between two bodies, that is ball to flat surface and flat surface to flat sur-face, and compared with the noise character of actual roller-chain driving. In consequence, the physical meaning of exponent in following relationship which was observed in the experiment of the noise of the actual roller-chain driving system was clarified.
P_∝Nⁿ
where P: mean pressure amplitude of noise, N: spindle speed,
n: exponent(=1.5 when no lubricant applied), (>1.5 when lubricated)

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In this report the influence of the stylus point radius on surface roughness curves were considered. In the first the limiting condition (γ<<i) of an approximate linear response of roughness curves and the approximate formula of the output cnrve of an cosine input was found. In the next the deformation of a cosine curve and also that of a triangle one were calculated.

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The results of a direct measurement of machining force in ultrasonic machining are described. The behaviour of machining force is observed by using piezoelements which are cemented or tightened between work piece and work holder.
The results obtained are as follows:
1) The impact phenomena between tool system and work piece system in ultrasonic machining can be explained as vibration problems. And the result of this theoretical analysis matches pretty well to the obtained experimental data, referring to magnitude of impact force and its phase lag between driving current.
2) The maximum value of machining rate in ultrasonic machining occurs when the feeding force is a little less than that for maximum impact force. And using a little higher driving frequency than the tuning frequency for end free condition, the most effective machining rate can be obtained.
3) From above mentioned results the author insists that the ultrasonic machining depends greatly on the impact phenomena between tool and work piece.

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Theoretical and experimental studies of the stresses owing to the transmission tensile force in a roller chain link-plate with a constriction of an arbitrary shape in the middle were reported in the author's previous papers, and the fatigue tests conducted on the bicycle roller chains and the small size roller chains for power transmission were discussed in another paper. In addition to those reports, comparative considerations between the calculated values and experimental results on the press-fit of the bushings for an actually used large size roller link were carried out, and effects of bushings-rift on the press-fit stress were explained in the latest report.
In succession to these previous studies, the present paper describes an investigation on the effect of press-fit of bushings. In order to examine the effect of press-fit of bushings into the holes of the link plate, various tensile loads were given to the phenolite link plate models which have various squeezed forms at the center of the plates, when the ratios of inner to outer diamaters of the circular eye-end parts are 1 : 1.5, 1 : 2.0 and 1 : 3.0, to which some initial force of press-fit was given beforehand, and the change of the stresses with load was observed by the photo-elastic method.
The relations between the forms of the link plates, the initial force of press-fit and the press-fit effect of the bushings, that is, the states of stress reduction and augmentation of the maximum load holding the press-fit effect, etc., have been clearly shown.
Moreover, comparing the above results with the experimental values which had obtained for the large size roller link for power transmission, we have examined the press-fit effect affected by the circumferential stress owing to the initial press-fit of the bushings.

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In electrical discharge machining based on condenser discharge system, the writer tried to pursue the relation of single strike condenser discharge between continual discharge (nearly practical machining condition) by means of micro-photographical observation on the surface crater.
As a result, in continual discharge, the writer found out that there were despersion and concentration phenomena of discharged crater distribution, and made their tendency clear.
if discharge is not intermittent, smooth machining cannot be obtained, so it is desiralc to disperse continual condenser discharging distribution.
The discharge of high frequency source alone, makes dispersion easy ; and superposition of proper high frequency source to concentrated discharge condition in D-C, source alone, helps the dispersion of discharges.

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Fig. 1 (a) shows a gear type condenser consisting of an internal gear and an external gear, both of which have the same module, pressure angle, and number of teeth.
The internal and external gears can move around the same axis, but are electrically insulated each other.
This pair of gears then turns to be an electric condenser of which capacity is uniquely defined by the relative position between two gears.
The gear type condenser can give a precise measurement of small angular displacement.
The sensitivity is about 1 volt for 1 second.
However in this paper will be discussed another way of case of this condenser e. the accurate way of indexing.
The internal and external gears used in the gear type condenser may have a pitch error. However it is quit e possible to make a very accurate division of 360°(indexing) by the number of teeth with this condenser. The error for indexing does not depend upon a pitch error of gears used in condenser.

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In this paper, the author verified experimentally that the analytical results obtained in the previous studies on flat superfinishing could be applied to the cylindrical superfinishing.
Further, he discussed the stone wear in cylindrical superfinishing on the basis of superfinishing resistance and pointed out that the optimum conditions of the abrasive stone could be determined by the critical ploughing force of the stone.

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The tool life tests of various types of ceramic tools are carried out to investigate the machining performances, the compatibilities for materials cut and the wear processes. Some of the Japanese ceramic tools have been proved to be better than any foreign product applied for the present test. As far as continuous machining of cast irons is concerned, ceramic tools are substantially effective, and normally the production rate in terms of net machining time can be increased about four times compared with the case of carbide tools. However, for general steels, especially adhesive steels, ceramic tools have not been reliable yet from a practical point of view. It is most essential for steel cutting to increase the toughness of ceramics.

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