55436. Carbide Tipped Adjustable Ogee Instile and Rail System 1-5/8 Dia x 13/64 to 1/2 x 1/4 Radius x 1/2 Inch Shank Set. Bits in these sets have profile and groove or rabbet cutters and ball-bearing guide mounted on a 1/2″ shank. Re-spacing of the components should only be necessary – using the provided shims – after the cutters have been resharpened. Guide straight cuts with the fence; use the pilot bearing only for cuts on curved rails or stiles.