Use your plunge router to accurately cut screw hole slots that will allow for seasonal movement of wide wooden parts, such as table tops. Both bits will cut a slot for #8 size screws and will cut a recess for the screw head up to 7/16” deep.
Flat counterbore has a 7/16” large diameter and should be used with square shouldered screws or screws using washers. The 82 deg. countersink has 1/2” large diameter and should be used with flat head wood screws. Solid carbide. 1/2” shank. USA