General causes of string breakage
1. Tuning over the pitch
2. Bridge is too high for steel strings (increased tension!)
Synthetic core strings:
1. Aluminium or chrome steel bands cut synthetic multifilaments at bridge or upper nut point (wooden parts not perfectly rounded or deep upper nut grooves)
2. Too high tension to avoid dead string effects and to prolong lifetime of synthetic strings
Gut wound strings:
1. String gets damaged by sharp edges of bridge or upper nut that cuts the gut core, for instance when d-bass strings are too long for individual instrument
Pure gut strings:
1. Gut gets damaged by sharp edges of bridge or upper nut groove, so that gut diameter will be finally too thin for the necessary tension and breaks
1. All parts in direct contact with string have to be well rounded and
2. should be coated with a soft pencil to let the string slide.
3. Donít twist string cross-wise on peg shaft.
4. For string with loop end, use protected fine tuners to avoid metal sharpness (E-string problem!)
5. For string with ball end, use fine tuner in right size (too small hooks are string killers)
6. Gut and gut strings are living strings: tuning above the pitch and back down to the pitch lowers tension between peg and upper nut. Lower tension ľ tone when on tour or not playing. The gut will recover and be fresh again for the next audience.
7. Gut or gut wound strings could break when brought and kept tuned in dry air. (gut will lose its normal humidity and shrink: tension increases)
8. Steel strings are sensitive to hot air while wooden instrument swells in hot, humid air so that E or A steel string may break