GM
A collection of various #piano tuning levers. A is likely over 100 years old. 
Discussion
GM pretty cool
Nice, I'd mess up an out of tune piano even further if I tried to tune it. All the stretching and stuff.
BTW what is the general approach to tuning the keys with more than one string? Do you go for as close tuning as possible or a gentle "chorus" for richer sound?
You mute all the strings in that note except 1 which is tuned to match the rest of the piano, then the muted strings are individually tuned to match the tuned string to create a unison.