Amana Tool 56274 Carbide Tipped Mortising Screw Cutter 3/8 Dia x 9/16 Inch Cut Height 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.