National Item Identification Number
00-947-6293
009476293
5210-00-947-6293
5210009476293
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)
GG0635
Required Categories
DESIGN TYPE
MATERIAL
WORKING SURFACE FLATNESS ACCURACY
DIAMETER
THICKNESS
C
Required Description
MASTER DOUBLE
GLASS, BOROSILICATE CROWN
0.00000200 INCHES NOMINAL
3.000 INCHE