The distance from the base surface to the end surface is10.16mm.

The taper is 1: 16, and the half cone angle is147' 24 ".

So the outer diameter of the small end = 26.568-10.16× (116) = 25.933 mm.

The big end is related to your effective length. According to the size of the small end and the half-cone angle above, it's there.