I’m starting this in a new topic, away from the Grimaldi stringing discussion, as I believe it merits emphasis.
I cannot stress enough the importance of contacting original makers and restorers when they still live regarding instruments of theirs regarding repairs and other issues. They will know regulations specifications, tonal preferences, and so forth, which may well not be what somebody else would do.
Indeed, especially of late since my waiting list is long, when asked to assess the condition and take on repair of several instruments, I made the site visit and assessed the instrument and then asked: have you contacted the maker? They invariably say no. I then contact the maker, fill them in on the condition and situation and ask if they would like to do the work. Many say yes please, and others tell me they trust me and send me parts and specifications. It is matter of respect for the instrument and the maker, particularly for some highly skilled makers who have had to scale down their work for personal reasons, but would greatly appreciate the income.
Another aspect of bringing an instrument to the maker’s attention is that I’ve had several well known builders express gratitude for putting them in contact so that they can upgrade the instrument to their current standards and to better now available materials.
Each instrument out there is part of a builder’s legacy, a child that has left home and represents our work.
In another situation, I heard through a piano tech list complaints about a recently made harpsichord. The university piano technician made many complaints and remarks and other technicians replied with (poorly informed) suggestions for remediation or legal routes! I deduced that this new instrument had arrived at a poorly climate controlled situation, as is very common here in the United States at least, where relative humidity can vary widely. I contacted the maker, who quickly got in touch with the university, drove down, and relatively quickly made the adjustments so it would work in the new environment.
Regarding restoration: I heard through a faithful colleague in the piano world that a piano tuner was complaining that I had “ripped off a client” with a restoration of a mid 19th century Broadwood piano, that it was untunable and unplayable. I called the client immediately, and drove out to the coast of Maine a few weeks later. Upon arrival I saw that the owner had the windows wide open (he lived on the ocean) and my humidistat showed 80% humidity. Alright! I assessed the situation, quickly tuned the piano (it had the short lived experimental threaded metal pinblock plate which works but does not feel at all like a modern pinblock when tuning) and used a heat gun to straighten a few hammer shanks. within 3 hours I was playing Chopin on the piano and the owner came in to apologize. We have become friends and I now care for that piano in downtown Charleston…also humid!
So, yes, please get in touch with original makers and restorers whenever possible. Not only is it an issue of respect, but also can prevent harm being done as Tilman pointed out! You can usually find a contact through grapevines such as this one.