I had a Crazy Parts vibrola installed on my SG Standard several months ago. I have broken 5 or 6 high E strings since, and all at the same place - the loop around the ball. I am using .010 D'Addario strings. I have checked the vibrola for burrs at the contact points with the ball end of the string and nothing seems amiss. When installing strings, I seat the ball so that the curve of the ball matches the groove in the vibrola. Is this a common problem? Should I polish the groove in the comb? Any other suggestions?