Jun 15, 2014 · How to Read a Grinding Wheel Spec. Diameter of grinding wheel x Thickness of grinding wheel x size of arbor hole . We will reference the AA Abrasives #60397 12x2x11/4 Pedestal Grinding Wheel T1 Vitrified A36 from our Vitrified Bonded Grinding Wheel Series. 12=Diameter x 2=Thickness x 11/4=Arbor Hole.