Pianoforte Manufacture

For tropical climates, an all-metal wrest-plank has proved its worth, the wrest-pins being held "friction tight" from the back of the plank. Fig. 3 shows an Australian and a German method of providing sufficient hold for the pin, at the same time allow ing it to be adjusted finely by the tuner. In order to prevent the two surfaces from rusting to gether, a very fine grade of gra phite is used as a lubricant. The washers have a projection which fits into a slot running down the threaded portion of the pin, which ensures that they move with it during all adjust• ments.

Standardisation.

The similarity in methods and design of the leading manufactures in all countries is accounted for by the necessity for standardisation of the keyboard, its height from the floor, the provision of room for the knees, the situation of the pedals, and the natural laws controlling the vibration of stretched strings. In the upright piano the wooden back forms a convenient base to which the ends of the case are glued, besides being the means for securing rigidity for the edges of the sound-board and a support for both iron frame and wrest-plank.

The peculiar form of the grand piano enables an immensely strong inner rim to be built up in one continuous bend, into which bracings are dove-tailed, and to which the key-bottom (support ing the key-board) is secured. This inner rim, on which the sound-board and iron frame are fastened, may be six inches deep, and from i" to 1 s" thick. Additional rigidity is further pro vided by gluing this unit to an outer rim, also of ply formation, about a foot deep and from 1" to II" thick. The skeleton forma tion of the case-work of a large Steinway grand is shown in fig. 4, but it must be remembered that the lateral stiffness of such a structure varies inversely as the cube of its length, and therefore small grands do not need such elaborate re-inforcement, the very smallest (4 ft. 3 in. to 4 ft. 6 in. in length) often having no brac ings at all. (S. A. H. See the BIBLIOGRAPHY under PIANOFORTE ; also Grove's Dictionary of Music and Musicians (1927-28) .