(under the class definition) Apparatus relating to the particular metal or alloy or the properties of either of which the device is made.
(1) Note. The mere recitation of iron or steel, per se, is excluded as being too common, however, specifying iron and steel or different types of iron and steel would be included.
SEE OR SEARCH THIS CLASS, SUBCLASS:
152, and the subclasses indented thereunder for such devices having a nonmetallic material forming part of the working chamber.
156, for such devices in which a resilient metallic material is utilized to form a working chamber surface portion.
178, for a working chamber plated wear surface.
SEE OR SEARCH CLASS 428, Stock Material or Miscellaneous Articles,
544+, for metallic stock material or intermediate articles from which parts for a rotary expansible chamber device can be made.
