The other qualities vital to quick movement and durability are lightness, elasticity and interchangeability of parts.
"My Attainment of the Pole"
Frederick A. Cook
The interchangeability of plate couplings is further destroyed by the fact already stated, that turned shafting is not, as a rule, of accurate gauge diameter, and the least variation in the pressure or fit of the coupling to its shaft is apt to cause a want of truth when the key bears on its top and bottom.
"Modern Machine-Shop Practice, Volumes I and II"
Joshua Rose
All during the nineteenth century scientists believed very firmly in the absolute independence of chemical elements and their utter non-interchangeability.
"Catholic Churchmen in Science"
James J. Walsh