Amana Tool 55285 Carbide Tipped Mortising Screw Down Shear Cutter 3/4 - 0.015 D x 9/16 CH x 1/4 - 28 Thread
Designed for use in standard lock mortising tools, these cutters can also be used in a standard router if mounted on a separate arbor.
For 1/2" shank use arbor #47614.
#55255 uses arbor #47616.
View all available Threaded Arbors for Screw Type Mortising Cutters.
Please note that these are the cutters only! The below tools do not include the arbors.