My dog has been deathly afraid of nail clippers since I found her as a stray a year ago....?

She couldn't have been more than 6 months old when I found her. She looks like a German Shepherd. I've only tried clipping her nails 2-3 times because it takes 2 people, one to restrain her and the other to clip her nails. She's ok smelling/seeing the clippers and putting them close to her feet, but the moment she feels them touch her nail, she turns into a wild, whining, bucking bronco, she tries to bite the clippers and does anything possible to get away. I've tried associating treats with them, distracting her, and trying to calm her verbally, (which worked with my other dog) but as soon as I actually try to clip, she's back to square one...... Any help would be appreciated.....