PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

21FK-820Nut,self-Locking,hexagon

Sps Technologies, Llc Dba PB Fasteners · NSN 5310-01-081-4690 · FSC 5310 · No Item Name Available
Verified by PartsTable
NSN 5310-01-081-4690 — this item is cataloged by the U.S. Government under National Stock Number 5310-01-081-4690. Primary manufacturer part number: 21FK-820.
Features
  • Nut,self-Locking,hexagon — FSC 5310
  • Nut Height: 0.328 INCHES MAXIMUM IN
  • Thread Quantity Per Inch: 20
  • Thread Series: UNIFIED NATIONAL JOINT FINE (UNJF)
  • Bearing Surface Type: CHAMFERED
  • Nominal Thread Size: 0.500 INCHES IN
  • Material: STEEL OVERALL
  • Surface Treatment: CADMIUM OVERALL
Applications
  • Structural fastening and assembly
  • Equipment mounting
  • Panel and housing attachment
  • Applications requiring Steel Overall construction
General Description

The Nut,self-Locking,hexagon, cataloged under National Stock Number 5310-01-081-4690, is classified within Federal Supply Class 5310 (No Item Name Available) of the Hardware and Abrasives group. The primary manufacturer of record is Sps Technologies, Llc Dba PB Fasteners. Government technical data includes 13 verified specifications, sourced from the Federal Logistics Information System (FLIS). This item has 7 commercial cross-references from 6 manufacturers, enabling identification through both NSN and commercial part number lookups. 9 verified substitutes exist in the FLIS interchangeability database. Current acquisition status: Active.

Technical Specifications
ParameterValue
NSN5310-01-081-4690
Primary Part Number21FK-820
Item NameNut,self-Locking,hexagon
FSC / FSG5310 / 53 — No Item Name Available
ManufacturerSps Technologies, Llc Dba PB Fasteners
StatusACTIVE
Nut Height0.328 INCHES MAXIMUM IN
Thread Quantity Per Inch20
Thread SeriesUNIFIED NATIONAL JOINT FINE (UNJF)
Bearing Surface TypeCHAMFERED
Nominal Thread Size0.500 INCHES IN
MaterialSTEEL OVERALL
Surface TreatmentCADMIUM OVERALL
Locking FeaturePREVAILING TORQUE ALL METAL DESIGN
Thread DirectionRIGHT-HAND
Width Across Flats0.741 INCHES MINIMUM AND 0.752 INCHES MAXIMUM IN
Nut StyleHEXAGON
LubricationSOLUBLE LUBRICANT
Thread Class3B
Lifecycle & Compliance
Acquisition StatusACTIVE
HAZMATNo
Verified Substitutes 9
5935-00-283-2056119582 INTERCHANGEABLE
Connector,receptacle,electrical
Bryant Electric
5930-00-629-2439011-1711 INTERCHANGEABLE
Switch,pressure
Ranco Inc Ranco Controls Div
5310-00-763-8901 INTERCHANGEABLE
Nut,plain,hexagon
5935-00-943-3869TRU-4174 INTERCHANGEABLE
Adapter,connector
Winchester Interconnect Rf Corporation
4720-01-020-2575AE1002208E0080 INTERCHANGEABLE
Hose Assembly,nonmetallic
Eaton Aeroquip Llc Dba Jackson North 1 Div Fluid and Electrical Distribution
5360-01-235-0203521-1929019 PIECE 58 INTERCHANGEABLE
Spring,helical,compression
Puget Sound Naval Shipyard and Intermediate Maintence Facility
3020-01-392-792332394 INTERCHANGEABLE
Gear Set,spur,matched
Oberdorfer Foundries Inc
1005-01-628-470532394 INTERCHANGEABLE
Rod,cleaning,small Arms
Barrett Firearms Manufacturing, Inc. Dba Barrett Firearms Manufacturing Inc
6350-01-667-4451855T-G24TL3 INTERCHANGEABLE
Alarm,audible-Visual
Rockwell Automation Inc Dba Rockwell Automation
Cross-Reference Index
Part NumberManufacturer
18GS88 Oshkosh Defense Llc (USA)
32394 Garrison Manufacturing Inc (USA)
21FK-820 PRIMARY Sps Technologies, Llc Dba PB Fasteners (USA)
21FK830 Sps Technologies, Llc Dba PB Fasteners (USA)
18GS88 Oshkosh Corp (USA)
424830-1 Naval Air Warfare Center Aircraft Division Joint Base Jbmdl (USA)
80131 Federal Screw Products, Inc. (USA)
Related Parts
5935-00-283-2056INTERCHANGEABLE
CONNECTOR,RECEPTACLE,ELECTRICAL
119582
5930-00-629-2439INTERCHANGEABLE
SWITCH,PRESSURE
011-1711
5310-00-763-8901INTERCHANGEABLE
NUT,PLAIN,HEXAGON
5935-00-943-3869INTERCHANGEABLE
ADAPTER,CONNECTOR
TRU-4174
4720-01-020-2575INTERCHANGEABLE
HOSE ASSEMBLY,NONMETALLIC
AE1002208E0080
5360-01-235-0203INTERCHANGEABLE
SPRING,HELICAL,COMPRESSION
521-1929019 PIECE 58
3020-01-392-7923INTERCHANGEABLE
GEAR SET,SPUR,MATCHED
32394
1005-01-628-4705INTERCHANGEABLE
ROD,CLEANING,SMALL ARMS
32394
6350-01-667-4451INTERCHANGEABLE
ALARM,AUDIBLE-VISUAL
855T-G24TL3

Frequently Asked Questions

What is NSN 5310-01-081-4690?

NSN 5310-01-081-4690 is a Nut,self-Locking,hexagon, manufactured by Sps Technologies, Llc Dba PB Fasteners, classified under FSC 5310 (No Item Name Available). Status: active.

What are the part numbers for NSN 5310-01-081-4690?

NSN 5310-01-081-4690 has 7 cross-referenced part numbers: 18GS88 (Oshkosh Defense Llc), 32394 (Garrison Manufacturing Inc), 21FK-820 (Sps Technologies, Llc Dba PB Fasteners), 21FK830 (Sps Technologies, Llc Dba PB Fasteners), 18GS88 (Oshkosh Corp) and 2 more.

What NSN replaces 5310-01-081-4690?

There are 9 known substitutes for 5310-01-081-4690: 5935-00-283-2056, 5930-00-629-2439, 5310-00-763-8901 and 6 more. Verify interchangeability with system specifications before substitution.

What are the specifications of 21FK-820?

Key specifications for 21FK-820: Nut Height: 0.328 INCHES MAXIMUM IN; Thread Quantity Per Inch: 20; Thread Series: UNIFIED NATIONAL JOINT FINE (UNJF); Bearing Surface Type: CHAMFERED. 13 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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