External Toothed Washers---BW
Zinc plated, Black Oxide, Zinc
Yellow plated, Plain.
Shape and Dimension
(1) The shape of tooth, twist angle and width of rim are optional; thest shall be uniform and the root of tooth shall be rounded as appropriate.
(2) The teeth of the washer shall be projected uniformly from both sides.
(3) The washers shall be free from remarkable deflection and eccentricity.
Measure the free height of a wash before test, then insert the washer, in the case of steel, between two steel plates, and the washer, in the case of phosphor bronze, between two brass plates,and compress it with a metric coarse screw thread bolt or a machine screw corresponding to the nominal size of the washer and a nut by turning to 1/3 rotation, and, after removal of the compression, measure the free height of the washer Calculate the ratio of this free height to that before test. The ratio shall not be lower than 5/6.
Small packing and Bulk.
JIS B 1255, ANSI B 18. 21. 1