The result of an indirect machining force measurement in ultrasonic machining is described. The mean machining force F_o is able to be determined from the contact duration τ of tool with a test piece and the static feeding force P, namely by the momentum theory
τ F_o=P. T so, F_o= P·T τ,
where T =ultrasonic oscillation period.
The duration of contact which is transformed to the electrical contact duration of tool with a test piece is measured by the cathoderay oscilloscope.
The results obtained are as follows ;
1) when machining rate is max., the machining force is max.,
2) wearing rate of tool is approximately proportional to machining force,
3) larger feeding force will be better for tougher test pieces,
4) with britller test pieces the ratio of machining rate to machining force is larger.

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We think electric-discharge cutting of metals to be as follows ; The conditions of electric currency, contact pressure of the pole on the work, surface speed of the pole, and machining fluids working together, change the frequency of arc discharge or the electric energy for each arc. Then the frequency of arc discharge or the electric energy for the arc influence over the cutting speed or machining efficiency.
We got many electromagnetic oscillograms of voltage waves in electric-discharge cutting for each value of surface speed and contact pressure. And by comparing these with the practical cutting results, we found not only the fact above-mentioned but also a fact that the eccentricity of electrode takes an important part, and others.

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In this paper, it is reported that tapping resistances in the mechanical tapping using a tapping attachment were measured by a mechanical tool dynamometer constructed newly and connected to an oscillograph through an electric resistance strain gauge. The materials used were low carbon steel, cast iron, brass and aluminium. The diameters of the hand tapps were 3/16'', 1/4'', 5/16'', and 3/8'' Whitworth. As the result, the tapping resistance is not merely affected by the tapping speed but depends on the diameter of the tap drill and the form of the chamfer and the flute of the tap.

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In recent years, many theoretical investigations about cutting heat have been published. In this report, these were compared with experiments, and it was found that R. S.Hahe's theory was most close to the fact. From these results, general equation about the temperature rise of workpiece during orthogonal turning was obtained, and the effects of this temperature rise; on cutting force and shear angle were discussed and shown experimentally.

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The temperature distribution in a cutting tool, the effect of tool shape and the dimensions on the temperature rise at chip-tool interface, and dissipated heat flow are experimentally analysed_by an electrolytic tank method. Under usual tool conditions, the temperature rise at chip-tool interfaceθ obtained in square-end straight tools is expressed as follows :
θ=CδQγ-0. 38 H-0.25 Lⁿ_L m-0.36 l-0.39 K^-1 η_oth
where, δQ : rate of heat flow into tool, cal/sec, γ : lip angle, H : height of square sectioi. of shank, L : length of overhang, n_L : 0.156+0.244 log (10m/H), K: thermal conductivity of tool material, η_oth : 1 for conventional cutting, 0.827 for orthogonal cutting, C : constant. The result is compared with approximate solutions for tool side, developed analytically by Trigger & Chao, Loewen & Shaw and Vieregge.
This showed that influences of m, l and γ are too exaggerated in these, for in these solutions a tool is regarded as a wedge and an existence of shank which restricts heat flow is neglected. The result above-mentioned makes us possible to get a reliable solution of chip-tool interface temperature.

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