PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

MS51959-81Screw,machine

Military Standards Promulgated by Military Departments Under Authority of Defense Standardization Manual 4120 3-M · NSN 5305-01-424-3581 · FSC 5305 · No Item Name Available
Verified by PartsTable
NSN 5305-01-424-3581 — this item is cataloged by the U.S. Government under National Stock Number 5305-01-424-3581. Primary manufacturer part number: MS51959-81.
Features
  • Screw,machine — FSC 5305
  • Thread Length: 0.497 INCHES NOMINAL IN
  • Fastener Length: 0.719 INCHES MINIMUM AND 0.750 INCHES MAXIMUM IN
  • Screw Surface Treatment: PASSIVATE
  • Thread Class: 2A A
  • Screw Material Document and Classification: QQ-S-763 FED SPEC SINGLE MATERIAL RESPONSE OR FF-S-86 FED STD SINGLE MATERIAL RESPONSE
  • Head Style: FLAT COUNTERSUNK
  • Thread Series Designator: UNIFIED NATIONAL COARSE (UNC)
Applications
  • Structural fastening and assembly
  • Equipment mounting
  • Panel and housing attachment
General Description

The Screw,machine, cataloged under National Stock Number 5305-01-424-3581, is classified within Federal Supply Class 5305 (No Item Name Available) of the Hardware and Abrasives group. The primary manufacturer of record is Military Standards Promulgated by Military Departments Under Authority of Defense Standardization Manual 4120 3-M. Government technical data includes 16 verified specifications, sourced from the Federal Logistics Information System (FLIS). This item has 1 commercial cross-reference from 1 manufacturer, enabling identification through both NSN and commercial part number lookups. 2 verified substitutes exist in the FLIS interchangeability database. Current acquisition status: Active.

Technical Specifications
ParameterValue
NSN5305-01-424-3581
Primary Part NumberMS51959-81
Item NameScrew,machine
FSC / FSG5305 / 53 — No Item Name Available
ManufacturerMilitary Standards Promulgated by Military Departments Under Authority of Defense Standardization Manual 4120 3-M
StatusACTIVE
Thread Length0.497 INCHES NOMINAL IN
Fastener Length0.719 INCHES MINIMUM AND 0.750 INCHES MAXIMUM IN
Screw Surface TreatmentPASSIVATE
Thread Class2A A
Screw Material Document and ClassificationQQ-S-763 FED SPEC SINGLE MATERIAL RESPONSE OR FF-S-86 FED STD SINGLE MATERIAL RESPONSE
Head StyleFLAT COUNTERSUNK
Thread Series DesignatorUNIFIED NATIONAL COARSE (UNC)
Screw Surface Treatment Document and ClassificationQQ-P-35 FED SPEC SINGLE TREATMENT RESPONSE
Countersink Angle80.0 DEGREES MINIMUM AND 82.0 DEGREES MAXIMUM
Head Diameter0.452 INCHES MINIMUM AND 0.507 INCHES MAXIMUM IN
Thread DirectionLEFT-HAND
Internal Drive StyleCROSS RECESS TYPE 1
Departure From Cited DocumentAS MODIFIED BY MATERIAL
Screw MaterialSTEEL COMP 304
Nominal Thread Diameter0.250 INCHES IN
Thread Quantity Per Inch20
Lifecycle & Compliance
Acquisition StatusACTIVE
HAZMATNo
Verified Substitutes 2
5305-00-719-5021MS51959-81 INTERCHANGEABLE
Screw,machine
National Aerospace Standards Committee Aerospace Industries Association of America Inc Not for Rfq or Solicitation Use
5305-01-424-3572 INTERCHANGEABLE
Screw,machine
Cross-Reference Index
Part NumberManufacturer
MS51959-81 Military Standards Promulgated by Military Departments Under Authority of Defense Standardization Manual 4120 3-M
Related Parts
5305-00-719-5021INTERCHANGEABLE
SCREW,MACHINE
MS51959-81
5305-01-424-3572INTERCHANGEABLE
SCREW,MACHINE

Frequently Asked Questions

What is NSN 5305-01-424-3581?

NSN 5305-01-424-3581 is a Screw,machine, manufactured by Military Standards Promulgated by Military Departments Under Authority of Defense Standardization Manual 4120 3-M, classified under FSC 5305 (No Item Name Available). Status: active.

What are the part numbers for NSN 5305-01-424-3581?

NSN 5305-01-424-3581 has 1 cross-referenced part number: MS51959-81 (Military Standards Promulgated by Military Departments Under Authority of Defense Standardization Manual 4120 3-M).

What NSN replaces 5305-01-424-3581?

There are 2 known substitutes for 5305-01-424-3581: 5305-00-719-5021, 5305-01-424-3572. Verify interchangeability with system specifications before substitution.

What are the specifications of MS51959-81?

Key specifications for MS51959-81: Thread Length: 0.497 INCHES NOMINAL IN; Fastener Length: 0.719 INCHES MINIMUM AND 0.750 INCHES MAXIMUM IN; Screw Surface Treatment: PASSIVATE; Thread Class: 2A A. 17 total characteristics are documented in the Federal Logistics Information System.

Validated with multiple authoritative sources, including Government, OEM, and Certified sources.
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