Stabbing or piercing, e.g. for making sieves (dimpling B21D22/04; perforating by punching B21D28/24)

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Other methods for working sheet metal, metal tubes, metal profiles (deforming one surface of tubes helically by rolling B21H3/00; upsetting B21J5/08; working metal by removing material therefrom B23; embossing B44B) > Stabbing or piercing, e.g. for making sieves (dimpling B21D22/04; perforating by punching B21D28/24)