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MS21075 : Mil-Spec Hardware

MS21075 : Mil-Spec Hardware Specification
Nut, Self-Locking, Plate, Two Lug, Floating, Reduced Rivet Spacing, Low Height, Steel, 125 KSI, Ftu, 450°F

MS21075 CAD DrawingClick on drawing for larger view


1. MATERIAL: Steel Grade 1035 (UNS G10350) per AMS 5080 Grade 1050 (UNS G10500) per AMS 5085 Grade 4130 (UNS G41300) per AMS 5350 Grade 1040 (UNS G10400) per ASTM A682 Grade 1042 &UNS C10420 per ASTM A576 Grade 4340 (UNS G43400) and Grade 8740 (UNS G8740) per AMS 6322.

2. FINISH: Cadmium plate in accordance with QQ-P-416 Type II Class 2. The plating type and class of dry film lubricated nuts are optional if the nuts meet the salt spray requirements of QQ-P-416 Type II.

3. DIMENSIONING AND TOLERANCING: Dimensioning and tolerancing shall be in accordance with ANSI Y14 5M


5. THREADS: Threads in accordance with MIL-S-8879

6. SURFACE TEXTURE: In accordance with ANSI/ASME B46 1. Unless otherwise specified the surface roughness shall not exceed 125 micro inches.

7. LUBRICANT: Dry film lubricant approved in accordance with MIL-N-25027. Other lubricants soluble in the cleaner specified in MIL-5-8802.

8. EDGES: Break all sharp edges and remove all burrs.

9. FLOAT: Float of nut element portion of assembly shall not be less than .020 laterally and longitudinally from centered position nut body shall be capable of engagement with a bolt in the maximum misaligned position maximum axial float .020 inches for .190 and smaller, .030 for .250 and larger nut misalignment shall not exceed dimension “B” the nut and base portion of the assembly shall form one integral unit and the surface assembly shall provide a bearing for the nut

10. PART NUMBER: MS21075 L 5 = Nut self-locking with dry film lubricant 2500-28

  • MS21075 Basic Military Standard Number
  • L “L” denotes dry film lube
  • “-“ denotes dry film lube
  • 4 Denotes thread size dash number
  • E UNJF-38 with eyelets
  • “E” denotes with eyelets, “N” denotes without eyelets
  • Absence of “E” or “N” denotes with/without eyelets (inactive for newdesign)


  • 1. Dimensions in inches
  • 2. In the event of a conflict between the text of this standard and the references cited herein the text of this standard shall take precedence.
  • 3. Unless otherwise specified, issues of referenced documents are those in effect at the time of solicitation.
  • 4. Design and usage limitations. These nuts are designed to develop the tensile strength of bolts and screws with an ultimate tensile strength of 125 KSI based on the cross sectional area at the basic pitch diameter of the thread. These nuts are designed to be used on 3A external threads. These nuts shall be used in accordance with the limitations of MS33588. Only nuts which there are qualified products listed on QPL 25027 shall be used.
  • 5. MS21075 supersedes NAS 1068.

Interchangeability Relationship

MS21075 nuts can universally replace NAS 1068 nuts of like material, thread size, lubricants (dry or non dry film) and rivet spacing. But NAS 1068 nuts cannot universally replace MS21075 nuts.

Need the Spec?

Click here to download MS21075 Specification
(PDF Format).

Great Lakes Fasteners
2204 East Enterprise Parkway
Twinsburg, Ohio 44087

Ohio: 330-425-4488
Nationwide: 800-589-4578
Fax: 330-425-4705

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GLFTechnical Fastener Supply specializes in a wide range of industrial and military specification (MIL Spec) fasteners; including MS fasteners, AN Fasteners, and NAS Fasteners.