ALFRA RotaBest High Speed Steel-Cobalt Annular cutters have specially designed cutting geometry for immediate centering, smooth cutting and low torque. Our ¾” Weldon shank includes two clamping surfaces and one countersink for dual use in RotaQuick tool holders. Each cutter has an internal bore for ejector pin and coolant supply, conical grinding and is compatible for all quick change and weldon shank tool holders.