Take the wheels off of the servos and tuirn on the radio. are the servos buzzing? Move the appropriate stick from stop to stop and return to neutral. Are the servos buzzing?

If they are not in both tests, the problem is in the linkage set up and not the servos. Look for binding or vertical alignment problems. I have had servos with perfectly aligned linkage buzz when a vertical load was being placed on them by the linkage. You could measure and eyeball the linkage all day and see that it wa inline with the servo arm, but fail to note that there was an angular difference vertically in the linkage.

Also look for a clevis pin going through the servo arm that is too tight.

I use a large pair of end cutters or a Dremel cut off wheel to cut my 4/40 wire with. Then I file the end square if I used the cutters. If your really desperate, I suppose you could use a hacksaw if the wire was properly clamped in a vise, but I wouldn't want to.