Is string design of the zither and the modern (upright and grand) piano have that in common? I hink that string design of the zither and the modern (upright and grand) piano have a lot in common, namely the design of the string holding is, with some convention, identical here. Yes, of course, the string tension on the zither is many times less than on a modern piano. EVERYTHING else can be said to be identical. Therefore, if sandpaper (1000) is used on the zither at the moment the pin is loosened, then why can't a corrugated cardboard shim have the right to be setting in hole of a piano's pinblock too? Screw, rather than hammer, the pin everywhere to rid the zither and piano of loose pins.
By the way, the zither pin has a left-hand thread may be it's creator been right handed, regards,Max