Originally Posted by COPEY
That's a point that's rarely made. When I first started stringing I thought I was doing something wrong, that I had flawed technique. After a while I discovered that it was normal, but you seldom hear people discuss straightening the mains; it's almost always the crosses.
Some machines require more attention to the mains than others. Depending on the design of the clamps, some push the mains aside when clamping crosses more than others. It's hard to avoid, but, unless the strings are really grabby, the clamps are usually what cause mine to need straightening.