Screws can be made in various sizes with a variety of threads. RMS threads can also be cut. Knobs can be replaced and made to match others on a microscope. Racks and pinions commonly need replacing as do stage clips.
Mirrors – I do not silver mirrors using mercury but I have occasionally silvered using Rochelle salts. However, most mirrors cannot be removed from their original holder without cracking. It is easier to make a new mirror holder containing a modern mirror which can be substitued for the original when the microscope is being used, this keeps the original mirror intact whilst allowing the microscope to function properly. I have a variety of modern mirrors which I can adapt so that they look more in keeping with the rest of the microscope.
Bullseye condensers – bullseye condensers with articulated arms can be made if necessary, this will usually involve finding a picture of an original to copy. (see image below)
Colour matching – It is not possible to fill in small patches of lost lacquer. Applying new lacquer on top of old will damage the original lacquer. I can however, re-lacquer one piece of a microscope. For instance, if the tube of the microscope needs re-lacquering but the rest of the microscope’s lacquer is intact I can do just the tube. I will do my best to match the colour.