I don't know of any human nail clippers that could handle an adult pit bull's nails.
Here's a bunch of info about nail cutting: viewtopic.php?f=7&t=12899
I personally use this type of nail clipper:
Oooh....those are my favorite nail clippers.....I won't use anything else. Someone lost the ones I bought for work and and literally had a hissy fit.
You never know when it will strike, but there comes a moment at work when you know that you just aren't going to do anything productive for the rest of the day.