Published on 20. May 2013 by Johannes Huefken
Last week I was in Timisoara, Romania's second largest city, German Timisoara. Until World War II, this city was mainly populated by Danube-Swabians. Among other things, we visited two organs there.
Since you did not receive a contribution last week, I would like to give you today a small impression of this city that flourished after the fall of the dictator Nicolae Ceausescu in 1989.
Now to the keyboard:
In the last article we glued the keyboard panel. Today it is the turn of the keyboard frame. In the second blog post I already hinted at the construction of the harpsichord manual. The harpsichord keyboard is a so-called "two-armed keyboard". This means that the key is stored in the middle. Like a rocker, the force at the rear end acts upwards when the front button is pressed. The board on which the keys are stored in the middle is called a balance beam. First I would like to explain why I used hardwood for the frame.
Since only the thin harpsichord back will later be under the keyboard, the keyboard must be self-supporting. This means: it must be so firm that the keyboard does not sag from below in the middle without a support. The balance beam must therefore be dimensioned accordingly. It must be taken into account that the balance beam must not only support the keys, but also withstand the force transmission of up to 10 fingers at the same time without yielding noticeably. In general, the keyboard frame should be flat and only as thick as necessary. When using hardwood, the limit is probably around 14 mm and for the balance beam at 20 mm. In addition to the statics, the more stable fit of the balance beam pins, which are nailed into the balance beam, speaks in favour of a balance beam made of hardwood. These guide the keys.
The wooden joint of the frame is traditionally slotted and tapped. But in my opinion there is nothing against a modern wood connection with dowels.
The picture shows a notched corner. This is where the register mechanism will later find its place when the keyboard is moved into the bass or treble for transposing.
In the next article, the keyboard panel is transferred to the frame. There are several work steps that are to follow one another without a break.