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National Stock Number:
5210-00-947-6293
Federal Supply Class:
5210
National Item Identification Number:
009476293
Description:
OPTICAL FLAT
Detail:
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.
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Manufacturer Information:
| GG0635 | 81348 | FEDERAL SPECIFICATIONS PROMULGATED BY GENERAL SERVICES ADMINISTRATION WASHINGTON DC |
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Techincal Specification:
| CASE | PROVIDED | | DEPARTURE FROM CITED DESIGNATOR | ABNM | | DESIGN TYPE | MASTER DOUBLE | | DIAMETER | 3.000 INCHES NOMINAL | | MATERIAL | GLASS BOROSILICATE | | NONDEFINITIVE SPEC/STD DATA | II TYPE AND 2 CLASS | | WORKING SURFACE FLATNESS ACCURACY | 0.00000200 INCHES NOMINAL | | THICKNESS | 0.6875 INCHES NOMINAL |
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