truing

true +‎ -ing.

truing (countable and uncountable, plural truings)

1. The alignment (and cutting) of a wheel (especially a grinding wheel) such that its surface is concentric with its axis.
   • 1956, Grits and Grinds, Norton Company, page 41,

     The wheel slides are purposely slightly under-compensated, causing the work to approach an oversize condition after several truings.

   • 1969, Machinery, Volume 75, Industrial Press, page 78,

     As many as twenty titanium alloy test specimens can be ground between truings.

   • 1986, R. L. Mahar, Grinding with Superabrasives, Robert I. King, Robert S. Hahn (editors), Handbook of Modern Grinding Technology, Chapman and Hall, page 106,

     CBN^{[cubic boron nitride (abrasive)]} wheel roundness to within .0001 inches (.0025mm) is considered satisfactory; however, roundess^[sic] to 1 micron (.000040 inches) or less will extend the number of parts between truings.

truing

1. present participle of true

• Turing, ungirt