The highest frequency of VHF crystal units, that can be obtained by lapping is considered to be about 75Mc/s. This limit seems to be caused by the vibration loss, which probably comes from the roughness of the quartz surface.
From this point of view, the authors have studied polishing of crystal plates, which was expected to make the frequency of the crystal units higher.
In this Report I, methods of working and measurements applied to polished crystals are described. That is:
(1) the general explanation of all working process,
(2) the eccentric loading and the measurement by a pneumatic micrometer necessary for getting the highest parallelism of quartz plates,
(3) the method of "Optical Contact" which is also required to secure the surface accuracy of plates, and
(4) the measurement of surface topography of plates by MBI-Fizeau fringes.

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The main purpose of this research is to seek experimentally the influences of shearing velocities on the shearing characters and to make clear the relations between the static shearing behaviers and the dynamic ones at the practical shearing velocity on the ordinary mechanical presses. In general, in order to know the shearing characters, we use universal testing machines, but the ratio of the practical shearing velocity to the one obtained by testing machine reaches over 10⁴ : 1, so it is very significant to do the dynamic shearing tests. To carry out the perfect shearing tests, we must record the shearing stroke, the shearing force and the time. The author performed the circular blanking tests (Fig. 8), and measured the shearing force i. e. the blanking force by the piezo-crystals (Fig. 5), and the blanking stroke in use of the photo-tubes, that transformed the punch stroke into the variation of the quantity of light brought into the photo-tubes, which was later changed into the photo-current (Fig. 1, 2 and 3). The produced piezo-electricity and the photo-current were so slight, that the author had to amplify them by the D. C. amylifiers (Fig. 9 and 10), and this outputs were directly led respectively to the horizontal and vertical deflecting plates of the cathode-ray tube. Thus the author obtained the shearing diagrams directly on the screen of the cathode-ray tube (Fig. 20), and the time was measured simultaneously by the intensity modulation of the cathode ray tube (Fig. 11).
The tested materials were usual rolled plates about 0.8mm thick of zinc, aluminium, copper, mild steel, 60 : 40 brass, German silver, and phosphor bronze (Table. 4). The tested clearances were six kinds between 0.048mm and 0.362mm (Table. 3). The numbers of stroke of press were changed between 28 s. p. m. and 190 s. p. m. (Table. 2). The tests were performed, of course, in the room temperature.
Thus, the author sought the influences of the shearing velocity x on the shearing resistance k_sm, the shearing work (i. e. energy) W, the sheared edges, etc. (the data will be found in the next report, Vol. 25, No. 9 ). By these investigations, it was made sure that for the above materials the relations k_sm∝(x)ⁿ and W∝(x)^n' were substantiated in the range of tested shearing velocities including the static shearing velocity (Fig. 2440). Here, n and n' are the constants concerning the sort of materials. Zinc is the most affected by the shearing velocity, and n=0.056, n'=0.044. For mild steel, n=0.016 and n'=0.011. For copper, n=0.015 and n'=0. 012. For aluminium, n=n'=0. 008. And for other materials, n and n'≤0.004, so it has been made sure that there are nearly no influences of the shearing velocities in the room temperature.
The influences of tensile strain rates on the tensile strength etc. has been particularly well studied by many foreign and domestic investigators, whose results coinside well with the author's shearing tests about the tendencies and the values of n. This fact shows that the tensile factors predominate in the later period of shearing.
From the above experimental results, for the materials popular to press-working except zinc, the dynamic shearing resistance and work at the practical working velocity are at most about 20% greater than the static ones (Table 6 and 7 in the next report), so we can utilize the results of static shearing tests.
On the other hand, the author measured the length of the punch-stroke till the point of the maximum blanking force (Fig. 45 and 46), the shape of sheared edge (Fig. 41, 42, 43 and 44), the dimension (Fig. 47, 48 and 49), and the deflection (Fig. 50 and 51) of sheared blanks, and the flowed grain structure near the sheared edge (Fig. 52),

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Unbalance and vibration of a Japan-made sewing machine (DDW-Type) were studied. Both the needle and its holder of this machine move up and down in its running condition, and therefore they produce unbalane force in its vertical direction. This unbalance force may, however, be cancelled by attaching a certain balance weight to its mainshaft, but by this attached balance weight a new unbalance force may be produced in the horizontal direction. Theoretically we are able to make the total unbalance force completely zero in one direction between the two (vertical and horizontal) directions, but at the same time that in another direction becomes maximum. Therefore, the practical sewing machine of DDW-Type is not made to become the state that the total unbalance force in one direction betw een the two may become zero or maximum in its running condition. This sewing machine has several parts of mechanisms, such as feeding mechanism, which move in only one direction. These parts of course produce unbalance forces in its running condition, but it may be seen from aforesaid facts that they cannot be cancelled by attaching any balance weight to its rotation part. All these unbalance forces in the machine were shown in this paper, and also it was found that in DDW-Type machine, the total unbalance forces are respectively equal to 2550 gr-cm in vertical direction, and 130 gr-cm in horizontal direction.

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The direction of a normal of a small plane surface, such as the ones of Vickers Diamond Pyramid, cannot be determined accurately by autocollimation, for the diffraction effect appears because of the apparent minuteness of the diameter of the collimator lens. Hence a new apparatus was designed.
The apparatus is shown diagramatically in Fig. 1 and 2. The microscope is constructed by an objective Ob and an occular Oc, and it also has a half silvered mirror H and a cross line graticule X. When the cross line is illuminated, its primary image is formed at Y. When a mirror is placed at the middle point between Y and the work point B of the microscope, its normal is parallel to the optical axis of the microscope, the secondary image of the cross line is formed at B, and then, the cross line is visible at the centre of the view field.
When tne small mirror is tilted around S (Fig. 1) by an angle of θ, the cross line is displaced by the amount (y-b)mθ at the field stop A, and the displacement can be measured by a micrometer occular.
The performance of the apparatus is studied by introducing the parameters of m (magnification of the objective) and n=x/y.And the following results are obtained;……
1) The sensitivity of the measurement is calculated by eqs. 9 and 10, and the results of numerical calculation are shown in Fig. 3.
2) The lower limit of the area of the small plane surface to be measured can be obtained by eq. 13, and the numerical results are shown in Table.3.
3) The maximum angle of θ is calculated by eqs. 18, 19 and 20 and the numerical results are shown by full lines in Fig. 5, '6 and 7.

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In this paper continued from part 1, we made an experiment on the effect of lapping pressure, lapped quantity, sphericity of balls used and supplying interval of lapping compound upon cutting resistance when the radius of steel balls was about 1 mm.
Then we found following results,
(1) in the case of cast iron lap, there were limits in suitable lapping pressure according to the ball size, and the supplying interval of lapping compound had no influence on them,
(2) in the case of suitable lapping condition, the cutting resistance was proportional to lapping pressure or the lapped quantity, and its proportional constant was different according to lap materials,
(3) in the case of nylon lap, lapped quantity was not much connected with lapping pressure, but sphericity was proportional to lapping pressure,
(4) in the case of cast iron and nylon lap, variation of the cutting resistance was comparatively small, and the sphericity increased when cutting resistance decreased gradually.

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In order to measure the length by counting the number of interference fringes observed in a field of interferometer, the counting apparatus was made on trial. This apparatus is composed of the phototubes to pick up the interference fringes, reversible electronic and mechanical counter, and cathode ray tube to read the fringe fractions. Counting rates in excess of 10KC have been achieved with this apparatus.

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