Dimensions of widths across flats
This Japanese Industrial Standard specifies the dimensions of widths across flats applied to threaded fasteners and spanners and the dimensions of widths across flats corresponding to the thread nominal diameters of hexagon head bolts, hexagon nuts, hexagon socket set screws, and hexagon socket head cap screws.
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General tolerances for linear and angular dimensions and geometrical tolerances (not to be used tor new designs)
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