National Item Identification Number
01-204-4081
012044081
5210-01-204-4081
5210012044081
National Stock Number
Item Name
OPTICAL FLAT
Federal Supply Class
5210
Description
A flat, transparent piece of glass, generally of fused quartz, with one or both principal surfaces polished to within a few millionths of an inch of a true plane. It is used in conjunction with a monochromatic light source to measure the flatness of precision finished surfaces, and to determine the distance and parallelism between precision finished surfaces by comparison with known standards. In operation the flat is superimposed, reference surface downward, on the parts under test and when illuminated by monochromatic light the rays reflected from the reference surface are either reinforced or neutralized by the rays reflected from the surface under test producing interference bands which reveal any variations in the thickness of the film of air between surface under test and the flat. Excludes optical parallels.
Commercial and Government Entity Code (Supplier Data)
Reference Numbers (Part Numbers)
2306121
Required Categories
III END ITEM IDENTIFICATION
THE MANUFACTURERS DATA
MANUFACTURERS CODE
DESIGN
Required Description
4920-01-198-0052
22380
2306121