cone-shaped or bell-shaped articles, e.g. insulator caps

Full Title

Making hollow articles not covered by a single preceding sub-group (essentially from sheet-metal or uniform thin-walled tubes B21D, e.g. B21D41/00, B21D51/00) > Shaping hollow articles with different cross-section in longitudinal direction, e.g. nozzles, spark-plugs > cone-shaped or bell-shaped articles, e.g. insulator caps