Some of these “boutique” shops build their instruments using components — soundboards, rims, pinblocks, plates — from specialist companies, while others insist on making nearly everything themselves. Most of these builders will complete, in a year, roughly as many instruments as, say, Steinway or Bösendorfer — their own instruments largely handcrafted — will finish in a day.

David Rubenstein, Los Angeles, California

“Actually,” says piano builder David Rubenstein, of Los Angeles, “it's more a question of how many years per piano than how many pianos per year!” Rubenstein, who works mostly alone, has built only two instruments since he began in 2002. He builds two models, a 12' 2" grand ($325,000) that is currently the world's largest commercially available piano, and an 8' grand ($175,000). The larger instrument has 97 keys, extending the bass to the C an octave below the lowest C of a standard 88-note keyboard. A musician and potter by training, Rubenstein says, “I originally wanted to make pianos because they are beautiful. My current feeling is that there are pianos I would like to see and play that won't exist unless I make them.”

Rubenstein says that, except for the stringing scale, he designed the entire piano himself. He also built the rim and rim presses, and even made the veneer used in the rim. “I make my own keyboards and keyframes,” he says, “and also offer this service to technicians and rebuilders.” Rubenstein makes his own soundboards and ribs from rough lumber. Although he has sometimes made his own pinblocks, he generally uses blocks made by André Bolduc, of Canada. Currently, most of the action parts and hammers he uses are made by the German firm of Louis Renner.

Rather than using traditional cast iron for his pianos' plates or frames, Rubenstein designed a steel plate welded together from pieces cut by CNC waterjet. “My instruments are truly one-off products, and my system of steel-plate making permits a wide latitude of design possibilities not possible with cast iron,” he says. “These are just a few things that distinguish me from all other piano makers, be they large concerns or other boutique makers.”

Luigi Borgato, Italy

If it's the fabricated steel plate that sets Rubenstein's instruments apart, for Luigi Borgato it's the fourth string. The 49-year-old Italian maker builds large grands featuring four strings per treble note, instead of the usual three. The idea for the fourth string, he says, was suggested by Beethoven's request for more strings in the treble of a fortepiano built for him by Viennese builder Conrad Graf — an attempt to overcome the composer's growing deafness by getting more sound out of the instrument.

Another historical idea inspired Borgato to build a pedal piano — actually, two instruments played by one player — so that works composed for pedal piano by Schumann and Liszt, among others, might be performed and heard as their composers had intended. Borgato's version stacks his 9' 3" concert grand atop a 13' instrument fitted with 37 pedals similar to those found on an organ. A piano technician by training, Borgato finished his first piano in 1991, and continues to build his instruments one at a time — a process that, he says, takes 1,120 hours per piano. As one would expect for such handcrafted instruments, Borgato's pianos are expensive: the Model L 282 Grand Coda costs more than $200,000, and the Double Borgato runs over $320,000 (both prices before taxes).