To what degree are the edges of optical flats bevelled?

Explanation

Explanation:- Edges of optical flats are generally beveled to 45 o by suitable grinding and polishing to make edges free from any chips. Optical flats are cylindrical with the working surfaces flat and are of two types Type A It has only one surface flat. The working surface of this type of flat is indicated by an arrowhead on the cylindrical surface pointing towards the working surface. It is used for testing the flatness of precision measuring surfaces of flats, slip gauges, measuring tables, etc. Type B It has both surfaces flat and parallel to each other. It is used for testing measuring surfaces of micrometers, measuring anvils, and similar length measuring devices for testing flatness and parallelism.