If you find a PDF dated 1983 or 1994, discard it. Those revisions are obsolete and do not reflect modern manufacturing capabilities.
Establishes tolerances for flat washers (Grades A, C, and F) designed for use in bolted joints with diameters up to 150 mm. Key Specifications and Tolerances iso 4759 pdf
(full title: Tolerances for fasteners ) specifies the permissible limits of variation for the dimensions of threaded fasteners and associated parts. It ensures that components from different manufacturers fit together consistently. If you find a PDF dated 1983 or 1994, discard it