An analysis of the longitudinal oscillation of both conical and exponential horns as used in supersonic machining shows that their amplification factors become maximum when adequate concentrated masses, like tools, are attached to their ends.
In both cases, the greater the ratio of the radii (√S₀/S_l) the greater the maximum amplification factor.
For the same value of (√S₀/S_l) the the amplification factor of conical horn is smaller than that of an exponential horn, but in the former case, larger concentrated mass can be attached to its end.

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Impact actions of sphere collided with semi-infinite elastic and plastic body were analysed. Force and deformation due to impact were presented as the function of diameter (D) and velocity (ν) of sphere and material factors.
The differences between the analytical results and the experimental formulas reported previously were compared by the exponents on diameter and velocity of sphere. The results are shown in table 1.
For the impact force of sphere, diameter effect in the elastic impact is equal to that in the plastic impact, but velocity effect in the former is larger than that in the latter. The experimental result on diameter effect is all but the same to them, and that on velocity effect is the middle of them.
For deformation, which involves chordal diameter, depth and volume of indentation, diameter effect in the plastic impact is equal to that in the elastic impact, but velocity effect in the former is a little larger than that in the latter. Theoritical results of the plastic impact are identical with the experimental results.

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In order to explain the influence of the cooling of workpiece by the application of cutting fluid on the toolchip interface temperature θ_t in the successive orthogonal cutting, the temperature rise of cooled workpiece θ_pw is calculated with the graphic difference method. This temperature rise composing a part of the shear plane temperature θ_s changes widely under the usual cutting and cooling conditions according to the cooling ability h, and decreases with decrease of the cutting speed V_c or the number of rotation N and increase of the ability h.
The cooling effect of workpiece causes the lowering of θ_l through the lowering of θ_s, and it is remarkable in low speed and/or light cutting. The relative importance and role of coolings of chip, tool and workpiece in usual cutting fluids and their applying method are discussed in sample calculations.

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Metal working shops in our country also must consider production applications of ceramic cutting tool materials, because in some foreign countries ceramics for this purpose have already found successful application in production set-ups. However, in our country, either its industrial application or the production of ceramic materials has been still very backward.
The purpose of this test is for quicker practical applications of home made ceramic tools and also for analysing the wear process of a ceramic cutting tool material, type B ceramic, produced by way of experiment. The test result has revealed that type B ceramic tool can cut Meehanite cast iron 2.5 times as fast as one of the best carbide tools under shop conditions. The economical machining conditions with type B ceramic tools have been investigated at the same time. One must bear in mind that the primary problem to improve the quality of ceramic tools is to prevent the cutting edges from chipping of either a largeor small scale.

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The design and experiments on spherical lapping of both bulb and stem for electronic tubes, which are to be used in submarine cable amplifiers, are described here.
The results which are considered to be applicable for obtaining the good contact between bulb and stem are as follows :
(1) Works can be spherically-lapped with spherical zone-shaped ebonite laps and with a universal holder.
(2) Through all three stages, the same combination of laps should be used, and works can be polished precisely, even without pitch-made polishers, causing no serious scratches on glass surfaces.
(3) When the stem is lapped, the concave lap is positioned on the stem, and when the concave lap is Mapped with the convex one, the concave one is positioned under the convex one. By this reversal of the position, the reproducible contact between bulb and stem with high accuracy is expected.

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