The unevenness of the thickness of plate film was measured with “Out of Roundness Tester”. A test piece of round mild steel bar, which had been accurately cylindrically ground, was chrome plated and its out of roundness was measured with “Out of Roundness Tester” to determine the change of roundness during the plating.
The change of roundness was always small when the test piece was plated in rotation independent of the position of anode plate; while, it was sometimes rather larger in stationary plating dependent upon the positions of two poles.