Abstract
The wringing force is a very important characteristic of the block gauges, but so far there have been few reports that give qualitative explanation on the cause of the wringing phenomenon. This study aims at making a theoretical analysis of the wringing phenomenon and substantiat-ing it by experimentation. In this study it is also intended to clearly define cohesive force, tangential resisting force, wringing torque and bending moment that are considered related to the wringing. The present report presents an analysis on the cohesive force and the following conclusions were drawn:
(1) The tensile strength which has heretofore been given a rather vague definition should be divided into cohesive force and tensile strength.
(2) The cohesive force can be considered to develop from the surface tension of oil existing between the wringing surfaces.
(3) The cohesive force is noted in vacuum.
(4) The contact angle in the practical wringing conditions is some 85 degrees.
