Steinway B New Pinblock Installation

This piano was very difficult to tune and had issues with jumping pins and tuning instability.
Just a consideration….. if any one reads this….. lol. Beware of where you purchase a piano. Pianos that are subject to high humidity and or salty air can be problematic. Things like rust can form in places you cant see. This piano is a perfect example. I am fortunate my customer has the finances to do this restoration. 
Some don’t have the piano checked out by a qualified piano technician from "The Piano Technicians Guild", and when these problems are revealed after a purchase it can be upsetting.

[@oliverheaviside2539]

I have a Baldwin L from 1969. It has a “snapping” pin block. Short of replacing the pin block, do you know of a way to get the tuning pins to move smoothly?

[@Grandpurpose]

That's a great question and difficult to answer. I have loosened the string to remove it from the pin. I then backed out the tuning pin all the way and then drove the same pin back into the pinblock, re-attach the string and tune the note. See if that made a difference. If not the do the same thing but try a new tuning pin of the same size.. use a micrometer to measure the pin. I prefer Diamond brand pins. You will need to experiment. I think Baldwin had the 41-Ply Pin Blocks. Horrible to tune. Sorry but that's the best advice I can give you short of replacing the block. Good luck and please let me know if you had any success or tried something else that worked.High Humidity is also a contributing factor.
Best of luck, Kurt