Knabe grand

[Newton Hunt]

What is most likely here is that if the strings are breaking at the
terminal points it is metal fatigue or possibly some poor wire.

If the strings are breaking at the tuning pins you are dealing with
some poor tuners in the past who moved the pin too far up and down and
caused metal fatigue.

Contributing factors are age, number of tuning, excess bearing between
terminal point and tuning pins, possibly high tension scale, hard
playing, corrosion, stiction (bonding between contacted materials) and
climatic abuse.

Best solution is to resting the piano and be done with the problem. 
Knabes need new blocks, bridges, rescaling and other such work.

		Newton