In a very important next step, in 1962 Steinway pioneered the use of modern plastics in pianos with the introduction of Permafree™ action flange bushings made of Teflon. Replacing the traditional wool cloth bushings with an inert material that didn't react to changes in humidity seemed a revolutionary step toward ensuring a reliably free and consistent piano action. But in actual practice, the new bushings were far from trouble free — what Steinway didn't realize was that dimensional changes in the wooden flange would affect the Teflon bushing. As the flange swelled with humidity, it put more pressure on the Teflon, which in turn pressed tighter on the center pin, causing the action to feel heavy and sometimes sluggish. Conversely, when low humidity caused the flange wood to shrink, the Teflon bushing became loose in the wooden part, causing a noticeable click when the key was played. Steinway twice redesigned the Teflon bushings to overcome these problems, and the third iteration worked quite well. But in 1981, tired of bad press, and finding it difficult to educate piano technicians in the new methods required to service the Teflon bushings, the company replaced the solid Teflon with wool cloth that had been soaked in liquid Teflon, a process Steinway named Permafree II™. This process is still used today, with good results.
Now Mason & Hamlin has taken the idea of synthetic action centers to a new level. First, they have replaced the traditional brass or German-silver (nickel) center pins with stainless-steel needle bearings. "The needle bearings are much harder than traditional center pins," says Burgett, "and they're available in increments of one 10,000th of an inch, as opposed to increments of one 1,000th of an inch with traditional center pins. This gives us outstanding control of the fit." The other change was to replace the traditional wool cloth bushing with a composite material. The actual composition of that material is proprietary, says Burgett, who notes, however, that the new bushing material is harder than felt or Teflon and is very resistant to damage. "The new action centers are absolutely unchanged by humidity variations, and are very consistent from note to note. This means we have extraordinary control of friction and, therefore, of touchweight."
Other piano manufacturers, as well, are experimenting with composites. For example, the high-end German piano maker Steingraeber & Söhne is using carbon-fiber soundboards in its Phoenix System models. I even know of a few individuals who have attempted to build the entire structure of a piano — case, plate, pinblock, and soundboard — of composites, the dream being to create a lightweight grand piano that one or two people could easily pick up and put into a van. Such instruments would also conserve precious wood resources, and might stay in tune better than pianos constructed mostly of wood. But while the composite piano remains at this point only a dream, history has made one thing clear: As long as pianos continue to be built, nontraditional materials will have a place in their construction.
Steve Brady, author of Under the Lid: The Art and Craft of the Concert Piano Technician (Byzantium Books, 2008), currently works each summer as head piano technician at the Aspen Music Festival. The rest of the year he services and rebuilds pianos and teaches piano technology in Seattle. See his website at stevebradypiano.com/