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DIN 935-1:2013
Hexagon slotted and castle nuts - Part 1: Metric coarse and fine pitch thread, product grades A and B
The document contains dimensional and technical requirements of hexagon slotted and castle nuts with nominal thread sizes from 4 mm to 100 mm, metric coarse and fine pitch thread, product grades A and B and specifies their designation.
Deutsches Institut für Normung [din]