Pianos are made with high quality materials, so it isn't surprising that when they don't play well anymore, their parts can be used for other things.
Using parts for making other instruments is logical.
In 2015 I was Musical Director for our Homeschooling Co-op's adaptation of "The King and I" called "Anna, Governess of Siam".
For the production, I decided to make an authentic Thai Kim, which is a kind of hammered dulcimer, except that it has three strings for each note and two bridges that allow the string to be played on either side of each bridge.
The first step was to make the frame. I used hardwood from an old piano and the pinblock which will eventually be drilled for the tuning pins.
Then the bottom was attached.
Top soundboard added with sound holes:
Bridges fitted not glued. Notice the Pringles chip container tops in the sound holes. 
:
Refinished. Notice Pringles tops carved and painted gold:
Tuning pin holes drilled:
Tuning pins added:
Bridges and strings added:
Notes marked. Notice how the bridge divides the strings so that two different notes are available for each string group:
Final project with strikers made from treble hammers:
