Sometimes restringing and/or revoicing will transform a disappointing instrument into one that is a pleasure to play. Before the mid 1980s there was no historically authentic wire available for harpsichords and the material used - usually steel and phospohor bronze or spring brass was mostly too hard and did not sound good. These days we have good historically accurate wire available from various sources but sometimes the scaling of revival harpsichords necessitates the use of steel in the highest parts of the compass. Insufficiently stressed bass strings on a clavichord can be replaced with over-wound ones to improve the tension, the touch and the sound. The machine for making over-wound strings is capable of a very wide range of formulations with copper, tinned copper and brass winding wires all available. Harpsichords can be re-voiced with either delrin, celcon or bird quill, the latter being preferred whenever possible for its superior feel and because it is easier for players or owners to look after themselves. Clavichord tangents can also be re-voiced and listing cloth optimised.