The sliding phenomenon of cutting edges in grinding, which has an important effect upon the cutting mechanism of abrasive grain, has been theoretically analyzed and the formula for determining the life of cutting edges has been introduced.
From the viewpoint of chip formation in grinding, chip forms are divided into two main classes i.e. type-I and type-II chip forms. In type-I chip form, the chip thickness increases linearly at the beginning part of cut, and takes the maximum value that is smaller than the depth setting and then decreases.
In type-II chip form, the chip thikness increases linearly at the beginning part and gradually along the interference curve at the next part, and then takes the maximum value equal to the depth setting.
In type-I chip form, the length of elastic contact between cutting edges and workpiece surface is in inverse proportion to the interference angle on the occasion that workpiece enters from the elastic region into the plastic at the part where the chip thipness increases linearly and may be equal to the chip length in some cases.
In type-II chip form, except above-mentioned cases, there may be the case that the length of elastic contact has no relation to the interference angle on the occasion that workpiece enters into the plastic region at the part where the chip thickness increases along the interference curve.

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In order to study the key factors which predominate over the machinability of steel, the fundamentals of the wear phenomena of metal cutting tool was investigated. The electron micro-probe X-ray analyzer was used to uncover the wear characteristics of carbide tools in turning of mild steel and leaded-free-cutting-steel at a cutting speed of 150 m/min. Tool surfaces and the internal sections were subjected to the X-ray micro analysis after 40 minutes of machining.
The experimental data shows that only iron and its compounds adhered at the crater of the tool, and aluminum and manganese were detected at the leading land and the trailing surface behind the crater. At the flank wear surfaces, iron, aluminum and manganese coexisted. At the worn surfaces, including the flank wear and crater wear, cobalt was detected with much less intensity than inside the tool material.
Concerning the action of lead included in free-cutting-steel, it was concluded that a portion of the lead melted at the tool-chip interface and acted as a lubricant; whereas, the lead particles which were included inside the chip did not melt but acted as notches reducing the toughness of the chip.

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It is very difficult to obtain a long period vibrometer of small size because of a large influ-ence of solid friction existing in it. When the place of it where the solid friction may exist is made to vibrate with a high frequency, the influence of the solid friction may be expected to vanish to make comparatively easy to obtain a long period vibrometer of small size.
In the 1st report of our study, we have already explained the behaviour of solid friction existing between a gravity pendulum and its support for the case of its free vibration when the support is vibrated with a velocity amplitude far larger than that of the pendulum. The present paper treated the case of the forced vibration of the pendulum under the action of an exterior force of harmonic time variation type and moreover under the same conditions as in its free vibration, and obtained the analytical results such that the vibrating solid friction becomes equivalent to a fluid friction and moreover the damping constant h and the damping decrement ε' of the vibration system due to the vibrating solid friction are expressed by the following forms :
h=x_fω₀²/πAωΩ, and ε'= x_fω₀²/πAω,
where x_f : the solid friction displacement, ω₀ : the natural circular frequency of the pendulum, A : the amplitude of the vibrating support, ω : the circular frequency of the vibrating support, and Ω²= ω₀²-².
Of course, due to the vibrating solid friction, in the forced displacement vibration of the pendulum is raised a vibration with the frequency ω and moreover with the amplitude of (π²/8) (ω₀/ω) ²x_f, but this amplitude becomes negligibly small compared with the motion of frequency ω₀ to obtain a smooth motion of the pendulum.
Furthermore, for the case when Aω becomes not far larger than x, the resistance characteristics of the friction become to be nonlinear about x, and the frequency response of this nonlinear vibration system has the charaRcters shown as follows : For non-resonance state, the vibrating solid friction behaves like a fluid friction, and for the state of near resonance it behaves wholly like a fluid friction when the vibration amplitude of this system is small. When the vibration amplitude becomes large, however, the vibrating solid friction behaves with its natural character.

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The vibratory compacting is one of pressing methods to increase the density of compacts. The authors deviced the new method of vibratory compacting, trying to make the compacts more dense and uniform for improving the mechanical properties of sintered parts.
In order to ascertain the effects of the vibratory compacting, two kinds of sintered parts (one is produced with the vibratory compacting and the other with the static compacting.) are compared on their density, compressive yield stress and hardness.
The behavior of metal powder is observed and the density distribution in compacts is measured, with the special techniqe using X-ray and fine lead balls which is explained in the 1st Report.
Moreover, the vibratory state of the die is analyzed theoretically and experimentally.
The result revealed through the theory and the experiment is as follows :
1) The die continues to vibrate under the solid friction in the vibratory compacting process; that is, the metal powder is sliding on the surface of the die.
2) The vibratory compacting makes the sintered parts much more dense, uniform and strong than the static process.
3) By observing the behavior of powder and measuring the density distribution in compacts, it is clear that the vibratory compacting differs essentially from the static compacting.
4) The mechanism of the vibratory compacting may be understood through the vibration analysis.

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It seems that, nowadays, a theoretically accurate method of making a screw surface of a board is not known yet.
Applying the character of a involute helicoid, the author has derived the theory on making a screw surface of a board, and made a very accurate one by using this theory. This method has following advantageous points in comparison with some other approximate methods.
(1) The outside diameter, the pitch and the flank angle can be made as designed. In other words, the theoretically accurate screw surface can be made.
(2) The flank angle can be made into any angle that satisfies its purpose within the limit decided by the outside diameter, minor diameter and the pitch, on the basis of the character of a involute helicoid.
(3) The number of winding of a screw surface which is made of one board can be calculated.
Furthermore, the author thinks that this is the only method of making the theoretically accurate screw surface of a board, since it is theoretically impossible to make it of a triangular thread and the like of a board.

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The following oils and emulsions were used in machining high silicon aluminum alloys containing 18.819.8% Si with a carbide tool having the tip of P30 or K10.
The oils used were the sulfurized fatty oil-mineral oil blend, the chlorinated fatty oil-mineral oil blend, and their mixture.
The emulsions were composed of one part emulsifiable oils, which were made of each blend mentioned above and non ionic surface agent, and 19 part water.
The fluid was supplied, through a jet nozzle, from the bottom up along the tool flank at the rate of approximately 450 cc/min.
The cutting conditions were chosen as follows : cutting speed, 60200 m/min ; depth of cut, 1.5 mm ; feed, 0.075 mm/rev.
The flank wear with time and the roughness of finished surface were measured and the finished surface was observed microscopically by means of replica. The mechanism of the action of cutting fluids for high silicon aluminum alloys was discussed from the above results.
The main results are as follows.
Generally, the action of cutting fluid in machining those aluminum alloys with a carbide tool is about the same as in cutting steels.
The fluids containing sulfurized oil (not mixed with water) and emulsion containing chlo rinated oil show the critical point in the flank wear curve at the relatively early steag of cutting.
The fluids added with water give rather poor surface finish than active oils.

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The variation of the roughness of the finished surface in turning of cast iron was investigated in reference to the cutting time from the viewpoint of the tool wear and tool vibration.
The following conclusions were drawn from the experimental study :
(1) The increase of surface roughness immediately after the beginning of cut is caused by the wear of the end cutting edge and side cutting edge which are greater than the wear of the nose cutting edge.
(2) The surface roughness decreases during the operation when the nose cutting edge is worn out faster than other parts of the cutting edges, so that the actual nose radius increases.
(3) The final increase of the surface roughness near the end of the tool life is brought about by the excessive tool wear and the increase of horizontal vibration of the tool.

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