7. THE KEYBOARD - A PLEA FOR SPRUCE

Published on 29. April 2013 by Johannes Huefken

Today we will get into the subject of keyboards. In addition some thoughts from me, why the keyboard is such an emphasis for harpsichord builders as well as for organ builders.

The keyboard is the connecting piece between player and instrument. In the case of nonkey instruments, the player is directly connected to the instrument. Playing music is playing on an instrument, whereby the player forms a unit with the instrument. When such a necessary bridge - the keyboard - has to be in between, the highest goal is to connect the player to the instrument. The organ also has one or more keyboards. The trend towards purely mechanical instruments has been back for many years. "Purely mechanical" means that the key is connected directly to the tone valve via small wooden strips. In mechanical action, the player has a direct influence on how the valve is opened and how the pipe is supplied with wind the first time it responds. With this the organist wants to have the system that was already up-to-date half a millennium ago.

The more intensively I dealt with this topic, the more I had to admit that the harpsichord construction pays even greater attention to the finesse and balance and tactility of the keyboard than organ building does. I have no explanation for this. But after further contributions you will agree with me.

First of all, it should not be about the keycoverings, which one actually always sees and plays on, but about the basic body, which physically transmits the power. With a built-in keyboard, you can always see the basic body when you play a note and look at the side flank of the next note.

The comparison
Why spruce? A little excursion

1. the comparison

The keyboard is traditionally made of spruce. Tradition is good, but even better when you explain yourself. So why not oak? Oak is widely used in organ building. That is why, as an organ builder, I would like to compare this stable wood with spruce.

The following data comes from the informative and lovingly designed website: "Holzwurm".

Technical data of spruce
bulk density :	0.43 g/ccm
tensile strength :	80 – 90 N/mm²
compressive strength :	40 – 50 N/mm²
flexural strength :	65 – 77 N/mm²
shear strength :	4 – 12 N/mm²

–

Technical data of the oak
bulk density :	0,64 – 0,71 g/ccm
tensile strength :	90 – 110 N/mm²
compressive strength :	52 – 64 N/mm²
flexural strength :	90 – 110 N/mm²
shear strength :	12 N/mm²

Full-grown spruce tree

Why spruce? A little excursion

As a master organ builder I would like to take you on a short excursion into organ building. Oak has many advantages, not only its toughness but also its resistance to weather, fungal and insect attack. Nevertheless, oak has not established itself as keyboard wood on any keyboard instrument. Oak tends to warp when dried and is a very heavy wood. Spruce, on the other hand, dries quickly and has a low tendency to warp. Despite its low weight, spruce also has good strength values. That is why organ builders use this wood for abstraction. Abstract are the thin wooden strips in the organ, which are the mechanical connection between key and valve to the pipe. Some of these have a cross-section of only o.8 x 6 mm. This corresponds to 4.8 mm². So about 40 kg could hang on such a thin spruce strip, even though spruce is such a soft and light wood. In harpsichord making, poplar and linden were also used to make keyboards, but I chose the traditional spruce. In the next article I would like to explain to you how differently the wood works with a moisture change and how important it is to pay attention to the correct wood direction here. We will also start with practical production.