It is generally believed that the domestic-made machines are inferior in durability to the imported ones. The only factor for it is the inferior abrasion quality itself. Measurement process of strength and hardness is simple, but measurement of abrasion is more difficult, and moreover there being no standard for abrasion measurement, their comparative discussion is infeasible and the measured results are also unreliable. We have more than 10 varieties of abrasion testing machines, but owing to the lack of the measuring standard, we find no abrasion meter. Measuring condition under the least error will be summarized that to find special values for p (kg/cm
2) and v (rpm), which satisfy the following three conditions simultaneously, i.e., dL/dN=K, ∂L/∂p=0 and ∂L/∂v=0, where N denotes number of revolutions (=abrased distance). Prof. Okoshi found that the abrasion loss L=f (pv), and the error being expressed by dL, the solution can be found from next formula [numerical formula] After tedious experiments, the author has found p=25 kg/cm
2, v=500 rpm, which satisfy formula (1). Next, it has been realized that these conditions hold for all the test pieces having extremely different qualities. Basing on the above results, the auther has invented an "Abrasion Meter", to which the Japanese Patent No. 198863 was granted in March 1953.
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