E string constantly breaking

[pops1]

Another question--- where is it breaking, nut, tuner peg, or bridge. You may have a sharp spot on any of these.

[A-board]

I had the same problem with my mystery name pac rim beginner mando. A bit of careful filing at the tuning peg hole and a couple strokes of very fine sandpaper at the nut slot fixed it for me.

[HonketyHank]

Interestingly (to me anyway), I have broken a few E strings while loosening them relatively rapidly. On one mandolin where this happened, I was taking the tension off because I suspected the nut slots were cut for a lighter guage string. I had just started loosening with a couple of fast cranks and POW. I did dress the nut slots( and checked the tuner posts for sharp edges, finding none). Haven't had it happen again since.

I have also had them break while tightening fairly rapidly, which makes more sense to me. But a tight fit on the nut slot could make the tension on either side of the nut be unequal and then suddenly equilibrate resulting a shock load whether tightening or loosening.

And I too keep a few extra E strings on hand. I am pretty sure JustStrings.com has them available.