"The wheel is with hurdy gurdy what the bow represents for violin. It is the wheel which gives a soul to this instrument and makes it different from the others. (...) It is the wheel which determines the caracter of an instrument, which makes the part stand out, by the various turns given to it ; it is what one calls wrist-strokes."
The wheel is the heart of the hurdy-gurdy, it is an essential part, but it is also a delicate body. It is thus advisable to take the greatest care of it ; any operation of adjustement carried out directly on the wheel will be led with extreme carefulness.
The wheel must be perfectly round, and this is very delicate to realize on the hurdy-gurdy, when it turns out to be faulty. It is better, when the whhel is dismountable to place it on its axis, out of the hurdy-gurdy, and to improve it on a good turn.
It should not be buckled, i.e. that its faces should not present any perceptible side displacement when the wheel turns.
The angles should not be sharp, but slightly rounded.
Its surface must be very smooth and not present any irregularity, nor asperity, in particular on the edges.
One should obviuosly never touch the surface of binding (or circumference) with anything ; it can ruin the rosin film. A trace of greasy susbtance on the surface of the binding destroys the wheel irremediably !
The rosin is a purified resin, used for the instruments the strings of wich are rubbed, and whose characteristic is to present a coefficient of friction wich decreases considerably when the movement goes quicker. It thus makes possible to maintain a vibration by simple friction on the string made of hairs or a wheel wood.
Currently, very good rosins in the form of breads of yellow or black color can be found. Buy good rosin for violin. It is also necessary to be careful about the quantity, neither too much nor too little. It is better to pass some often and little at each time.
Indications and precise for the maintenance and the adjustement of the following elements :