Where can I find out just about a piece of antique medical equipment I adjectives from my Dr. grandfather?

You might want to call your local medical society. Many enjoy experts who would be willing to cooperate to you - especially if your grandfather was a local!
http://www.ama-assn.org/ama/pub/category.
Wouldn't you know. Google query on Medical Antiques
brought up.
http://www.medicalantiques.com/.