27/64″ Counterbore (For GC121 Bearing)
Quality high speed counterbores used to set your GTC bearing system. Select your counterbore for your chosen size ( outside diameter of the bearing). Then choose the pilot to fit the shank diameter of your pivot pin. Proper cutting depths are 0.50″ for all bearings except GC102 with a cutting depth of 0.66″.
27/64″ counterbore for CG121 bearing system.
Choose your preferred pilot / shank.