The special hammer felt used in the Renner hammer is produced by the Würzen Felt Company, in the former East Germany, which supplied vintage Steinway and other quality pianos their special hammer felt for over 100 years. The felt became unavailable for several decades following World War II, during the Russian occupation, and became available again with the reunification of Germany. It continues to be the finest hammer felt produced in the world, resulting in the widest possible harmonic and dynamic tonal range with a minimum of voicing required.
The molding used in the Renner Premium Blue and Blue Point hammers is a special species of Walnut wood, grown in Germany. It is carefully selected for its uniform, lighter weight, and responsiveness. It is aged naturally, prior to final conditioning, to assure long term stability and performance in different climatic environments.
Each of our hammerheads incorporates the exclusive Renner T-Clasp™ to maintain the desired felt tension and even weight distribution within each hammer. This unique clasp is made from a proprietary, surface-coated, hardened steel, which is used to lock the felt to the base of the molding without damaging individual felt fibers. To assure uniformity, each clasp is optically sorted and matched by computer to assure the correct dimensions and alignment of the stems. The clasps are then inserted electronically into each hammerhead, one-at-a-time, applying equal pressure to both sides of the hammerhead, to assure uniform tension and perfect centering and alignment of each clasp. Each hammerhead is then hand inspected individually to assure absolute perfection.
Our unique hammerhead presses allow for the perfect centering of the outer and under felt on the hammer molding, with special sensors controlling the amount of pressure and temperature applied to each individual hammer across the scale. This protects the structure and integrity of the felt during the pressing process, and results in the optimum tension and responsiveness of each individual hammer.
Selecting Replacement Hammers
The grand hammers are made in 3 basic weights, with an additional weight in the Hamburg Collection, and 2 boring sizes which will fit 80% of the pianos you are likely to encounter. 3 universal sizes are also available, which can be custom bored, shaped, and tailed, for the remaining 20% of the grand pianos. See the chart below for specifics.