PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

15X521Screw,machine

Napco International Llc Dba Napco International Inc · NSN 5305-00-579-5808 · FSC 5305 · No Item Name Available
Verified by PartsTable
NSN 5305-00-579-5808 — this item is cataloged by the U.S. Government under National Stock Number 5305-00-579-5808. Primary manufacturer part number: 15X521.
Features
  • Screw,machine — FSC 5305
  • Head Style: FILLISTER
  • Thread Class: 2A A
  • Thread Series Designator: UNIFIED NATIONAL COARSE (UNC)
  • Thread Length: 0.667 INCHES MINIMUM AND 0.750 INCHES MAXIMUM IN
  • Nominal Thread Diameter: 0.216 INCHES IN
  • Internal Drive Style: CROSS RECESS TYPE 1
  • Nondefinitive Spec/std Data: 1 TYPE AND 4S STYLE
Applications
  • Structural fastening and assembly
  • Equipment mounting
  • Panel and housing attachment
General Description

The Screw,machine, cataloged under National Stock Number 5305-00-579-5808, is classified within Federal Supply Class 5305 (No Item Name Available) of the Hardware and Abrasives group. The primary manufacturer of record is Napco International Llc Dba Napco International Inc. Government technical data includes 13 verified specifications, sourced from the Federal Logistics Information System (FLIS). This item has 9 commercial cross-references from 9 manufacturers, enabling identification through both NSN and commercial part number lookups. 12 verified substitutes exist in the FLIS interchangeability database. Current acquisition status: Cancelled.

Technical Specifications
ParameterValue
NSN5305-00-579-5808
Primary Part Number15X521
Item NameScrew,machine
FSC / FSG5305 / 53 — No Item Name Available
ManufacturerNapco International Llc Dba Napco International Inc
StatusCANCELLED
Head StyleFILLISTER
Thread Class2A A
Thread Series DesignatorUNIFIED NATIONAL COARSE (UNC)
Thread Length0.667 INCHES MINIMUM AND 0.750 INCHES MAXIMUM IN
Nominal Thread Diameter0.216 INCHES IN
Internal Drive StyleCROSS RECESS TYPE 1
Nondefinitive Spec/std Data1 TYPE AND 4S STYLE
Thread Quantity Per Inch24
Minimum Tensile Strength60000 POUNDS PER SQUARE INCH LBS
Head Diameter0.334 INCHES MINIMUM AND 0.357 INCHES MAXIMUM IN
Fastener Length0.750 INCHES NOMINAL IN
Thread DirectionRIGHT-HAND
Head Height0.134 INCHES MINIMUM AND 0.148 INCHES MAXIMUM IN
Lifecycle & Compliance
Acquisition StatusCANCELLED
HAZMATNo
Verified Substitutes 12
5305-00-010-0673 INTERCHANGEABLE
Screw,machine
5305-00-022-4455 INTERCHANGEABLE
Screw,machine
5305-00-145-7676 INTERCHANGEABLE
Screw,machine
5305-00-272-1700 INTERCHANGEABLE
Screw,machine
5305-00-273-5798N55P13006 INTERCHANGEABLE
Screw,machine
Lockheed Martin Corporation Div Rms
5305-00-273-583743S16467-512 INTERCHANGEABLE
Screw,machine
Navair and Navsea Managed Original Design Activity Dwg Not Material/parts Supplier
5905-00-351-6101 INTERCHANGEABLE
Resistor,fixed,film
5305-00-375-7412341-3801-1188598PC10 INTERCHANGEABLE
Setscrew
Naval Ship Systems Command
5310-00-383-4675100675 INTERCHANGEABLE
Nut,plain,slotted,hexagon
Dana Off Highway Products, Llc
5305-00-579-5807 INTERCHANGEABLE
Screw,machine
Cross-Reference Index
Part NumberManufacturer
100675 General Motors Corp (USA)
15X521 PRIMARY Napco International Llc Dba Napco International Inc (USA)
F761 PRIMARY Solventum Purification Inc. Div Filtration and Separation Division (USA)
MILS933TYPED Military Specifications Promulgated by Military Departments/agencies Under Authority of Defense Standardization Manual 4120 3-M
FFS92TYPE1STYLE4S Federal Specifications Promulgated by General Services Administration Washington DC (USA)
31095S Ford Motor Company (USA)
31095S Ford Motor Co Ford Parts and Service Div Government Part Sales (USA)
100675 General Motors Llc Dba General Motors Llc (USA)
100675 PRIMARY Chrysler Realty Company Llc Dba Daimler Chrysler (USA)
Related Parts
5305-00-010-0673INTERCHANGEABLE
SCREW,MACHINE
5305-00-022-4455INTERCHANGEABLE
SCREW,MACHINE
5305-00-145-7676INTERCHANGEABLE
SCREW,MACHINE
5305-00-272-1700INTERCHANGEABLE
SCREW,MACHINE
5305-00-273-5798INTERCHANGEABLE
SCREW,MACHINE
N55P13006
5305-00-273-5837INTERCHANGEABLE
SCREW,MACHINE
43S16467-512
5905-00-351-6101INTERCHANGEABLE
RESISTOR,FIXED,FILM
5305-00-375-7412INTERCHANGEABLE
SETSCREW
341-3801-1188598PC10
5310-00-383-4675INTERCHANGEABLE
NUT,PLAIN,SLOTTED,HEXAGON
100675
5305-00-579-5807INTERCHANGEABLE
SCREW,MACHINE
5996-00-915-3036INTERCHANGEABLE
AMPLIFIER,ELECTRONIC CONTROL
100675
5365-01-355-2647INTERCHANGEABLE
SHIM

Frequently Asked Questions

What is NSN 5305-00-579-5808?

NSN 5305-00-579-5808 is a Screw,machine, manufactured by Napco International Llc Dba Napco International Inc, classified under FSC 5305 (No Item Name Available). Status: cancelled.

What are the part numbers for NSN 5305-00-579-5808?

NSN 5305-00-579-5808 has 9 cross-referenced part numbers: 100675 (General Motors Corp), 15X521 (Napco International Llc Dba Napco International Inc), F761 (Solventum Purification Inc. Div Filtration and Separation Division), MILS933TYPED (Military Specifications Promulgated by Military Departments/agencies Under Authority of Defense Standardization Manual 4120 3-M), FFS92TYPE1STYLE4S (Federal Specifications Promulgated by General Services Administration Washington DC) and 4 more.

What NSN replaces 5305-00-579-5808?

There are 12 known substitutes for 5305-00-579-5808: 5305-00-010-0673, 5305-00-022-4455, 5305-00-145-7676 and 9 more. Verify interchangeability with system specifications before substitution.

What are the specifications of 15X521?

Key specifications for 15X521: Head Style: FILLISTER; Thread Class: 2A A; Thread Series Designator: UNIFIED NATIONAL COARSE (UNC); Thread Length: 0.667 INCHES MINIMUM AND 0.750 INCHES MAXIMUM IN. 13 total characteristics are documented in the Federal Logistics Information System.

Is NSN 5305-00-579-5808 still in active supply?

NSN 5305-00-579-5808 is currently cancelled. Check with the Defense Logistics Agency for current availability and authorized substitutes.

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