One remains astonished by the simplicity of the tools used to build the moulds of the bells. They have not changed much for centuries, except for the drawing of the profile of each bell. Now modelled on a computer, each profile is reproduced onto laser-cut plates. The templates are mounted on a pin and are used as guides in the manufacture of the mould. In the workshop, the technical references of each project are written in chalk. The bell illustrated here is intended for the medieval castle of Tiffauges in the Vendée department. Its diameter will be 720 mm and it will ring a C4.