A discussion of the manufacture of early scientific instruments where all of the work was by very basic tools and indeed many aspects of the manufacturing process had to be devised by the instrament maker. Now having obtained one of these fine instruments either for practical use or as a collectors' item, the task of renovating and repairing may need to be undertaken. The author shows some of the problems that could be encountered and ways of overcoming them. In many cases the availability today of materials or the actual manufacturing process that was used cannot be found and it is necessary to adapt modern technology in order to achieve the desired result. -- AATA