5310-00-564-0398 (1663-4)
NSN 5310-00-564-0398 (NIIN 00-564-0398) is a keyway washer in Federal Supply Class 5310, Nuts And Washers — a washer of nonresilient material usually having two parallel bearing surfaces. Manufacturer part number 1663-4 (Eaton Aerospace, LLC, CAGE 62983).
Key specs: 68 rockwell a minimum or 70 rockwell a maximum hardness; full characteristics table below. NIIN assigned January 1963; DEMIL A (none required); unit of issue EA (each), $0.53 gov standard price; ships at 0.01 lb / 0.0004 cu ft. Supersedes 1650-00-697-8613 (1963).