A notch is made on the ends of the fence panel rails. This is done so that you can insert the fence panel into our pre-punched line, corner, end and t (3-way) posts. Notches are never made on gates because gates are welded into a frame you connect gate to posts with hinges.
The notch (not including the taper we add) is ¼’ tall x ¾’ long. In other words…we take a RAIL that is 1” tall and clip it to fit into a hole in the POST that’s just over 3/4” tall and the rail is inserted into the post ¾”