Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
B21K—MAKING FORGED OR PRESSED METAL PRODUCTS, e.g. HORSE-SHOES, RIVETS, BOLTS OR WHEELS
B21K21/00—Making hollow articles not covered by a single preceding sub-group
B21K21/08—Shaping hollow articles with different cross-section in longitudinal direction, e.g. nozzles, spark-plugs
B21K21/10—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