SPECIFICATIONS OF BLÜTHNER PIANOS
Grand Piano Specifications
Blüthner Pianos have been exclusively manufactured in Leipzig, Germany since 1853. Members of the Blüthner family have always been in control of the production and have always adhered to the tradition of hand made quality.

Grands are Produced in Six Sizes:
Model: Length / Width / Weight
1: 9'2" (280 cm) / 5'6" (159 cm) / 490 kg
2: 7'8" (230 cm) / 5'4" (153 cm) / 385 kg
4: 6'10" (210 cm) / 4'11" (151 cm) / 320 kg
6: 6'3" (190 cm) / 4'11" (151 cm) / 285 kg
10: 5'5" (166 cm) / 4'11" (151 cm) / 265 kg
11: 5' (148 cm) / 4'11" (151 cm) / 240 kg
All models:
Height: 39 3/4" (100.5 cm)
Key height to floor: 28" (71 cm)
Pedal height to floor: 1 1/4" (3.5 cm)

Rim Construction and Bracing
The outer rim is made in two halves using up to 7 layers of veneers, laminated crosswise with water resistant glue.

The inner rim is laminated of at least 14 layers of select beech. These parts are carefully stored until a uniform moisture content of 8% plus/minus 1.5% is reached. The thickness of the inner rim is 40 mm to 46 mm, the thickness of the outer rim is 22 mm to 27 mm according to the size of the instrument.

The rim braces are glued in three layers, two of which on the outside are made of first class pine and the one in the middle is made of red beech for extra stability. One end of each brace is mortised into the inner rim, the opposite end of each brace is fitted into the back rail. To further secure the braces and rim, the braces are screwed to the rim and keybed and consoles are glued and screwed to the rim.

All models have four or five lengthwise braces and a crosswise brace made of red beech, 40 mm (1 1/2") thick, mortised and glued to the braces.

The number of length braces and the measurements of the brace material is listed below:
Model: mm / number
1: 65 x 120 / 4
2: 70 x 110 / 5
4: 65 x 110 / 4
6: 65 x 110 / 4
10: 65 x 110 / 4
11: 65 x 110 / 4

Pinblock
Extra select red beech cut into layers of 2 mm is glued crosswise together in 16 layers using water resistant glue, reinforced with a layer of quarter-sawn red beech. The thickness of the pinblock is 36 mm.

Soundboard and Ribs
The soundboard is made of clear, quarter-sawn solid spruce. It is varied in thickness by reason of acoustical design. Careful manufacturing assures the greatest responsiveness due to an optimal ratio of elasticity to density.
The ribs are also of select quarter-sawn spruce, graduated in width and thickness and feathered for flexibility and frequency response.

The number of ribs used is:
Model: number of ribs
1: 17
2: 13
4: 13
6: 12
10: 11
11: 11

The ribs are mortised into the inner rim and glued to the soundboard with water resistant glue. The whole soundboard is coated with a special kind of varnish.

Only fine grained, white, well seasoned spruce which originates from the Eastern Alpine regions is used in the production of Blüthner soundboards and ribs.

Bridges
The bridges of a Blüthner grand piano are handmade of solid maple, with a reinforcement in the treble, fitted with transmitting bridges where necessary. They are carved and fitted with bridge pins made of steel.

Strings
The treble strings and the core wire are of highest grade, strong, elastic steel wire. The high precision in production avoids differences in diameters, which ensures a clear tone without any falseness. The wrappings of the bass strings are of solid copper, the core of hexagonal diameter.

String Plate, Tuning Pins and Aliquot System
The string plate is cast in special iron which can support high tensions but it has also a damping effect, remaining inert to string vibrations. Its form is carefully calculated and specially designed for each model. The firm's name is cast into each plate. All agraffes are of brass and threaded securely into the plate.

Chromium-plated tuning pins of special steel, multiple threaded, are used.

A fourth string for every note in the treble section, which runs parallel to the normal strings, passes over the bridge but is elevated where the hammer strikes. This string picks up the vibrations sympathetically and enhances the overtone spectrum of the instrument.

Action and Hammers
The action is made by Renner according to measurements provided by Blüthner. This insures a smooth and fluid touch.

All parts are made of select sound hardwood, free from imperfections. All critical action felts and cloths are made of 100% wool, with manufacturers moth-resistant treatment, and are equal to the highest felt and cloth standards. Center pins are of nickel silver. All center-pin bushing material is pre-shrunk. The actions of all Blüthner grand pianos are designed and thoroughly tested for optimum performance and longevity.

The hammers are a fundamental part of the instrument which contribute substantially to the unique Blüthner sound. Crafted from the finest felt, arched over a core of walnut wood and individually voiced to perfection, the distinctive Blüthner hammers stimulate the purest vibrations of the strings.

Keys and Keybed
All 88 keys are made of spruce, The sharps are made of ebony and the white keys are covered with acrylic. It is also important that sensitive key balancing is performed to exacting specifications that ensure ease of repetition and control.

For the keybed, select spruce is glued together in several layers to a total thickness of 42 mm to 45 mm, depending on the size of the instrument. Red beech is inserted where the attachments of the legs are situated.

Pedals, Casters and Hardware
All grands are equipped with three pedals of solid brass. They serve for shifting the keyboard, sostenuto and sustaining.

The casters for all models have swivel stems and solid brass wheels three cm to seven cm wide according to sized of the instrument. The concert grand casters have a swivel stem and special double wheels on brass bearings, with a locking mechanism included.

All external hardware is of solid brass.

Chipping and Tuning, Regulation
The pianos receive a sufficient number of chippings and tunings consistent with the highest piano manufacturing standards.

The action is fully regulated during the period of settling of the entire piano. Before voicing the piano is given a final regulation. The hammers are carefully tone regulated by master craftsman to obtain a uniform tone level from note to note.

Seasoning and Settling of Piano and Action
The pianos are placed under moderately fluctuating temperature and moisture conditions until the various elements season and settle into a stress-balanced piano unit.

Leg and Lyre Construction
Legs are made of glued pine, twice veneered, mortised and wedged into the leg bracket, which is made of red beech. The lyre is also made of red beech, all parts firmly wedged together.

Fallboard and Lid
The fallboard is of 12-ply construction with a core made of pine. The lid is made of several layers of veneer, cross-banded, and with hard maple as the final covering.

Finish
As far as necessary all cases are stained, multiple lacquered, rubbed and polished by hand.

Cores and Glues

All lumber is seasoned for several years. Only then is the lumber kiln-dried to a moisture content between six and eight percent, glued with moisture resistant glue and properly seasoned after gluing.

Moisture resistant glue is used except where the size or construction of the part makes this impractical or undesirable.