Whiteside Screw Type Helix Mortise Cutter w/Downshear, 17/32 in. CD is designed to create precise hinge mortises with ease. This versatile cutter can be used in both hand-held and machine routers, featuring a down shear cutting design that ensures clean, splinter- cuts every time. The cutter has a 1/4-28 internal thread size and requires either a 1/4" or 1/2" shank Helix Mortise Arbor (HMA14 or HMA12), which are sold separately. It is a 2-wing carbide tipped cutter manufactured by Whiteside Machine Company in Claremont, North Carolina. The cutter measures 17/32" (.531") in cutting diameter, with a cutting length of 5/8" and an overall length of 7/8". Model Number: 13-531