Steinway Factory Tour
In a unique method used by Steinway for over a century, the inner and outer piano rims are bent into the shape of the rim as a single continuous piece. Before Theodore Steinway developed and patented this method in 1878, rims were made of separate pieces held together with joints. 18 hard-rock maple layers, each twenty-two feet long, are used to construct the rim of a concert grand piano. The layers are first coated with glue and stacked. The stacked layers are then glued into a single form of wood by bending on the rim-bending press, a giant piano-shaped vise. The rim-bending team centers the layers on the press and wrestles the wood into place with the aid of clamps.
The soundboard is a large wooden diaphragm with a wooden bridge centered on its top side. The piano strings pass over the bridge, and the bridge transfers the string energy into the soundboard. As a result, the sound of the strings is amplified. The soundboard is pressed into the shape of a dome, allowing it to withstand the combined downward force of 1,000 pounds from over 200 strings.
The Steinway soundboard is carefully formed, by hand, into a patented Steinway design. Close grained quarter-sawn spruce is used to make the soundboard because the wood is flexible enough to vibrate and therefore project sound, but strong enough to support the weight of the piano's strings. The soundboard is expertly tapered by a craftsman to be slightly thinner at the edges so that it can vibrate properly once it is glued to the piano's inner rim.
Before a soundboard can be placed into a piano case, the bridge must be notched for the strings that will pass over it. First, a heavy black graphite is applied to the top of the bridge. A three-pronged tool is then used to mark the points where the bridge will be pinned and notched. It takes years of training for the craftsman to know exactly where to place the notches.
To ensure cosmetic beauty for a wood-finished instrument, all of the veneer on a single Steinway piano is cut from the same tree. In the veneer room of the factory, veneer is cut to size, matched and identified with the piano number.
The piano rim is being transformed into a piano case. A wooden brace assembly is being custom fit within a rim structure. This network of bracing helps support the 340 pound cast iron plate. The braces fan out within the rim structure for stability and are secured into the rim by using a combination of fine joinery and maple dowels.
The arms of the piano are sanded into shape.
Here, a cast iron plate is being fit into a piano case. The 340 pound cast iron plate provides a rigid and stable foundation needed to hold approximately 40,000 pounds of string tension. Graphite has been spread over the portions of the cast iron plate that come into contact with the rim and pin-block. The plate is then lowered into the piano case, fitted, and then raised out of the case. The rim and pin-block surfaces that show print from the graphite indicate an improper fit with the plate and are shaved to eliminate gaps between the two surfaces.
Once the soundboard and cast iron plate are in the piano case, the piano is ready for its strings. With unerring aim, the stringer inserts a wire through the hole in a tuning-pin. A machine guided by the stringer turns the pin three times, wrapping three wire coils around it. The pin is then placed through one of the more than 200 holes in the cast iron plate and driven into the pin-block.
The action's felt hammers are made from a single strip of felt that is pressed into shape. To form the hammers, glue is first applied to the inside of the felt strip. The felt is then placed in a long, grooved copper form and pressed around a three-foot long wood rod into the pear shape of a hammer. Once the felt has been pressed and removed from the machine, the rod is sliced. Each piece becomes a hammer which is twirled onto a hammershank.
The wood of the hammershank is sometimes heated by a small flame to make subtle adjustments in placement.
The dampers prevent the piano strings from unintentionally vibrating after the strings have been hit by the hammers. A master technician painstakingly matches the damper felts to the strings. The technician must then reach underneath the piano and, with mirrors, adjust the levers that control each of the dampers.
In a process called the action weigh-off, each key in the keyboard is calibrated to have a consistent feel. Weights are placed on the key and lead is inserted into the body of the key until the pressure needed to push the key down is the same for each key.
The voicing process involves minute adjustments to the hammer, which are critical to the piano's sound and the distinctive personality of each Steinway. A master voicer makes adjustments to the hammer's resiliency by sticking the hammer's felt with a small row of needles, reducing its stiffness and thereby mellowing its tone. If the voicer wants to increase the brilliance of the key, he will harden the felt by applying a small amount of lacquer. The voicer must approve of the tone quality of each key.
A tone regulator listens intently to the piano's pitch and turns the tuning pins with a tuning hammer to adjust string tension. Once the piano has been regulated, it is ready for its final inspection.