CHAPTER IX.
THE CASE AND FRAMING OF THE PIANOFORTE.
The grand pianoforte is distinguished conspicuously from the upright, as far as concerns the principles of its construction, by the different function which its exterior casing exercises. As was stated in Chapter III, the exterior walls of the upright have no part in the bearing or resisting work that the iron and wooden framing performs. They exist chiefly for the purpose of giving support to the key-board and action, and of affording a foundation whereon may be constructed the elaborate architectural and decorative structure that, in its entirety, is denominated the pianoforte case.
The synonymous portions of the grand pianoforte, on the contrary, have a far more important duty to fulfill. While they are equally charged with the support of the key-frame and action, they are also an essential part of the wooden framing, are one and homogeneous with it, and, in fact, occupy much the same position as what is known as the “back” of the upright, as well as being the external and decorative coverings of the instrument.
The case of the grand is constructed of a series of continuous veneers, glued one upon another, and each extending completely around the periphery of the case. These veneers are glued at cross grain to prevent splitting and are applied to the pianoforte and bent into shape when in a heated state. The complete outline thus obtained is denominated the “continuous bent rim” and is a distinguishing feature of the modern grand pianoforte as made in America. Several eminent German makers, as Bechstein, also employ similar means of constructing the external walls. In England, on the contrary, the case is usually made out of one thickness of wood bent into the required shape by steam and joined in several places. This system provides for separate moldings for the bent and straight sides and for the rear portion.
The advantage claimed for the continuous bent rim is that the whole case, by this means, becomes so closely bound up with the rest of the structure as to become part of one homogeneous resonant whole, thus improving the general resonance and imparting a sostenuto and cantabile that can in no other manner be attained.
While data are lacking for the precise investigation of this claim, it is significant that the bent rim method has not only become universal among American makers—by one of them it was first devised—but has even made its way into European favor.
The case, after it has been bent in this manner into the proper shape, has to be decoratively veneered according to the style of ornamentation that is intended for it. The work of veneering these cases, whether for uprights or grands, need not be gone into here in detail. There are so many specialists in this department who confine themselves to the turning out of such veneered cases, and the whole matter is so far away from the principles of pianoforte construction, that it is not considered necessary to go into it here.
It is, of course, required to provide the case of the grand pianoforte with a system of wooden struts which bind it together and give it strength and resisting power. These struts are set into the case in the general form of the letter A, having the apex at the forward end of the case. At this apex they are crossed by another wooden strut running parallel to the key-board, which serves to bind them together and to mark the limit of the space to be occupied by the sound-board. These struts are not, as we may thus see, carried into the very front of the case, but are confined to that portion which is directly underneath the sound-board. In front of this space is left the gap through which the action is later to strike, and underneath is provided a key-bed to carry the action and keys. The key-bed joins the front portions of the bent rim and closes the casing in the front, thus providing a definite and uniform structure. Above the key-bed and in front of the gap is one of the most important parts of the entire instrument. It is called the “wrest-plank,” and is situated at the foremost portion of the case. This wrest-plank is built of a series of hard wooden layers, glued together at cross grain and adapted to be bored with holes in which are placed the “wrest-pins,” or tuning-pins, that control the tension of the strings. This block or plank must necessarily be of great solidity and be capable of holding the pins frictionally, so that they will not pull round under the immense strains that are imposed upon them.