mandrel vs trunnion

mandrel

noun
  • A round object used as an aid for shaping a material, e.g. shaping or enlarging a ring, or bending or enlarging a pipe without creasing or kinking it. 

  • A tool or component of a tool that guides, grips or clamps something, such as a workpiece to be machined, a machining tool or a part while it is moved. 

trunnion

noun
  • A similar rotational bearing comprising a rotating arc or ring sliding in the groove of a stationary arc, used in machinery to allow a workpiece to be moved relative to a fixed tool. 

  • A similar rotational bearing used in automotive suspensions. 

  • A shaft, held by a bearing, at each end or side of a rotatable object. 

  • One of the short stubby bearings on either side of a cannon; a gudgeon. 

How often have the words mandrel and trunnion occurred in a corpus of books? (source: Google Ngram Viewer )