Hang on, aren't track nuts 15mm?
Yes, but that's cycling weirdness. Normal M10 nuts are 17mm AF, normal M8 screws are 13mm AF. In order to use the peanut butter wrench for both track nuts and crank bolts, special cycling nuts and screws are made with odd sizes.
You haven't answered the question; what's the thread size of the screws which you don't like?