I do the entire range of repairs. On old uprights (regardless of make), the actions always need work. They were put together with hide glue, which fails after 50 years or so, and all the felt is either worn out or compressed, making the sound quality poor (This latter is also true of grands). All those little springs which make uprights work wear out too. Many old pianos still have ivory keys. Most people like to try and retain them, so I help by patching keyboards from my used ivory bin. (new ivory has not been available since the late 50’s).
Then there’s the strings. Regular piano wire has a useful, tunable, life of 60-80 years (without water damage). Bass strings usually die earlier, The copper or nickel windings come loose from the core wire, producing either a nasty buzz or a dead tubby sound after 50-60 years.
Most old pianos have some soundboard cracking, as a result of insufficient humidity in their environment. In grands, this is usually pretty serious, and involves a complex repair in which the strings and steel plate are removed, and the board recrowned and shimmed (and refinished). Uprights, which have an essentially flat board, do very nicely with a “glue & screw” repair, to stabilize the board and prevent changes in bridge bearing. (Steinway uprights on which I did this repair 20 years ago are still doing fine).
Pinblock replacement is generally necessary in about 50% of older grands, as the laminated ply of the original blocks has failed, making the piano untunable (particularly Knabe’s). Steinway uprights never have bad pinblocks, but they do often have cracked bass bridges which need repair.
Thus, a redo on almost any old piano can be quite complex, but many can get by with a set of new hammers, a regulation, and a double tune (If a flat piano is past the 80 year limit, the pitch cannot be raised to A440 using the original strings).
Now, in 2013, the “church basement” uprights, staple of my early career, the bar pianos of the speakeasy era, are all falling apart…The total overhaul they need is impractical. The 5′ baby grands which were churned out by Aeolian and Kimball in their thousands in the 30’s, and the Wurlitzer and Winter spinets of the 40’s and 50’s are simply not worth saving.
It has become necessary for me to make judgement calls on many of these pre-WW2 pianos. I generally recommend rebuilding Baldwin, Mason & Hamlin, Knabe, Sohmer, Chickering, Hardman, and , of course Steinway, pianos. Other, more obscure makes can actually be excellent, and even restorable, pianos, but the cost of a major repair cannot be recovered upon sale of the instrument. The customer’s sentimental attachment to the piano must outweigh these concerns. This is especially true for very old instruments, or unusual pieces like square grands.